Classic Rotary Phones Forum

I asked the following question on Stack Exchange but was told it was off-topic: https://networkengineering.stackexchange.com/questions/42193/pbx-co-trunks-analog-multiplexing-analog-version-of-pri

It's sort of technical in nature which is I presume why it was put on hold.

Does anyone know if they can maintain an analog connection between the central office and their house/business using just 1 cable, like PRI,  but with analog channels instead of digital? Is there a name for this type of technology to distinguish it from PRI?

I want the call quality and reliability of having as many separate landlines coming into the building as I needed outside lines, but the convenience that one large cable coming in offers - in addition to one cable, Direct Inward Dialing and Direct Outward Dialing are my primary concerns.

Nobody on the site I posted to was helpful, so thanks in advance to anyone who can help me out with this!


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EDIT: text copied from "other site" and pasted here for posterity


"PBX CO Trunks: Analog multiplexing (analog version of PRI)? [on hold]

I've been doing more research into PBXs, specifically trunk connection methods. My understanding is that there are 3 primary options:

    Separate telephone lines for each trunk line
    Primary Rate Interface (PRI)
    Session Initiation Protocol (SIP)

I'm trying to figure out what the best way would be to connect an analog-only PBX to the central office. I've already ruled SIP/VoIP out as being considerably inferior, from a quality and reliability perspective especially. PRI is preferable to SIP, but my understanding is that PRI uses TDM/digital transmission which would not be acceptable.

- - - - - - - - - - - - - - - - - - - - - - - - - -
Premise:

    Transmission must be analog, not digital, for call quality and reliability - the call quality should be basically the same as that with a separate standalone landline connection.

    Digits should be dialed immediately. I know many systems "hold" digits and then analyze the digits dialed using a "dial plan". Internally, this might be of some used. But if "9" is dialed for an outside line, I want the PBX to grab an outside line for the station and step out of the picture. The digits should be sent to the central office then as they are dialed, not all at the end (again, as with a separate, standalone landline connection).

    Going along with my second point, all central office connections, whether they are individual cables or one large one with separate analog channels, would have to be identical. Because the circuit will be grabbed as soon as "9" is dialed, all "features" (i.e. ability to make Long Distance/International calls) would have to be the same for each line/channel, since it would be impossible for the actual intended number to be analyzed. Basically, the call should be being routed as it is being dialed, not after.

    There's extreme controversy it seems regarding 9-1-1 and 9 9-1-1 going around (the linked petition will be impossible to force for systems such as the one I desire). I know that 9-1-1 will not be doing anything because to the central office, it looks like 1-1 has been dialed which could have easily been a switchhook mishap (I assume this is why 1-1 is not rerouted to 9-1-1). The PBX will be in a home environment (not a public system) and since I, most of the time, will be its only user, I will know to dial 9911 instead of 911 anyways. 911 should NOT connect to anything.

    I don't believe nesting PBXs will be a problem. I am going to buy a PBX that will support at least 50 stations, but one of the "stations" will end up being a corded switchboard PBX (PMBX or Private Manual Branch Exchange), and other "stations" may be other sub-PBXs that are PABXs, like the main one. Is there any way to use features like Direct Inward Dial from telephone stations to PBXs nested further down in the tree?
- - - - - - - - - - - - - - - - - - - - - - - - - -

I'm trying to figure out which networking technologies would best meet most, if not all, of my requirements. My guess is it would be some technology that lies between separate regular landlines and PRI, if there is one. The PBXs that will actually be used are arbitrary and irrelevant, but they will all be analog and have no digital support.

I believe something along the lines of an early 1970s analog PABX would end up being used (as is described here), but I am interested in what transmission technologies concerning the trunk lines should be used.

Is there a sort of medium between separate analog lines and PRI? I'm looking for a medium that will retain an analog transmission between the PBX and the Central Office, but the switching technology itself can obviously be digital (as all PABXs are). Is there any way to maintain an analog connection between the central office and the PBX without running separate regular landlines for each trunk? Analog will be needed to support good call quality for regular analog rotary and pushbutton phones, fax machines, and modems (including dial-up). I want whatever trunk technology is used to function like a standalone line without actually being 4 or 6 separate standalone lines. Costs aside, my primary concern with having standalone lines will be direct inward dialing as well as direct outward dialing. Even if there are 50 stations, there are only a few numbers I'd want to have DID and DOD for - otherwise, I want only ONE telephone number - and NOT as many numbers as there are trunks (this might be appropriate for a Key Telephone System but not a PBX), since I want one number to be used for Caller ID from any non DOD phone, which I don't think standalone lines would support.

If my internal extensions range from 1000 to 1500, the numbers I need supported for DID/DOD would be 1000 as well as a few other numbers between 1000 and 1200. I don't want to have to purchase a whole block of 200 "numbers" if that can be avoided (unless there is no additional cost).

I am estimating between 4 and 6 trunks will be required. Costs are not a concern, although since this will be installed in a home environment with 1 bill-payer, ideally they should be low.

Summary:

    No digital transmission (i.e. packet switching)
    Analog multiplexing is possible so multiplexing is fine if each individual circuit is analog.
    Routing as calls are dialed, not after
    Compatibility with DID and DOD

CLARIFICATION: I'm not asking anything about a PBX at all. I'm inquiring about the protocols used, specifically PRI, and if an analog variant of PRI (possibly a predecessor to PRI) exists."

I think you should summarize and post your questions here and not refer to another site.

I also think you should talk more about the eventual goal. Is this for some kind of commercial service or for pleasure ?
Connecting a PBX to a central office is not a goal, the benefit of that is the goal, I presume.

What kind of PBX are you connecting?  What kind of interfaces are available on that?

Analog trunks are rapidly coming out of style, have been for some time and the traditional DID service is not usually available anymore.  What many people, especially the VoIP folks today mean with DID is a different service.

How many simultaneous calls are anticipated ?   This determines the number of analog trunks you need.   Nobody does analog multiplexing via carrier systems anymore, except the cable company's coax systems.

The most prominent analog multiplex system was probably AT&T's L-carrier system, dead for decades.

Quote from: bellsystem on June 26, 2017, 05:18:03 PM
Does anyone know if they can maintain an analog connection between the central office and their house/business using just 1 cable, like PRI,  but with analog channels instead of digital? Is there a name for this type of technology to distinguish it from PRI?

Who is "THEY" ?
PRI is not an analog channel, it is ISDN over T1 carrier, or E1 carrier in most other places in the world, except the US and Japan.
CAS T1 service is almost extinct and is also not analog.

Quote
I want the call quality and reliability of having as many separate landlines coming into the building as I needed outside lines, but the convenience that one large cable coming in offers - in addition to one cable, Direct Inward Dialing and Direct Outward Dialing are my primary concerns.

The best quality today comes via VoIP, it can provide a much larger bandwidth than 3.5 kHz, but you need the right kind of PBX for that too.

Quote from: bellsystem on June 26, 2017, 05:18:03 PM
    Transmission must be analog, not digital, for call quality and reliability - the call quality should be basically the same as that with a separate standalone landline connection.

Call quality on analog systems is only best over very short distances when the entire voice path is metallic.  Ever since the T carrier was introduced this is rarely the case anymore, as virtually every communication is sampled 8000 times per second.

Quote
    Digits should be dialed immediately. I know many systems "hold" digits and then analyze the digits dialed using a "dial plan". Internally, this might be of some used. But if "9" is dialed for an outside line, I want the PBX to grab an outside line for the station and step out of the picture. The digits should be sent to the central office then as they are dialed, not all at the end (again, as with a separate, standalone landline connection).

This is a function of the terminal equipment, not the trunk or communication channel.  What kind of PBX are you using ?

Quote
    Going along with my second point, all central office connections, whether they are individual cables or one large one with separate analog channels, would have to be identical. Because the circuit will be grabbed as soon as "9" is dialed, all "features" (i.e. ability to make Long Distance/International calls) would have to be the same for each line/channel, since it would be impossible for the actual intended number to be analyzed. Basically, the call should be being routed as it is being dialed, not after.

    There's extreme controversy it seems regarding 9-1-1 and 9 9-1-1 going around (the linked petition will be impossible to force for systems such as the one I desire). I know that 9-1-1 will not be doing anything because to the central office, it looks like 1-1 has been dialed which could have easily been a switchhook mishap (I assume this is why 1-1 is not rerouted to 9-1-1). The PBX will be in a home environment (not a public system) and since I, most of the time, will be its only user, I will know to dial 9911 instead of 911 anyways. 911 should NOT connect to anything.

You will have to design your own PBX system and design the dialing plan according to your needs.  Any old commercial system, that has such features, as selecting outgoing CO trunks, can hardly be customized. You will have to use it the way it was built.

Quote
    I don't believe nesting PBXs will be a problem. I am going to buy a PBX that will support at least 50 stations, but one of the "stations" will end up being a corded switchboard PBX (PMBX or Private Manual Branch Exchange), and other "stations" may be other sub-PBXs that are PABXs, like the main one. Is there any way to use features like Direct Inward Dial from telephone stations to PBXs nested further down in the tree?

Never heard the term PMBX, at least I don't recall.    I am not sure how a single station can make a meaningful PBX.

The term 'PBX' has no technical significance in terms of capabilities or technical features.  It only labels a telephone system as being capable of operating as a private branch of the public switched telephone network. It is a local switching center and only calls to the "outside" are passed to the PSTN. How those connections exactly are made is entirely different matter.   A PABX was typically a PBX in which the stations could dial other stations, or possibly dial a trunk connection, without attendant involvement.   But, as technology progressed into digital electronics, PABXs after perhaps the early 1980s, were simply called PBX, because nobody would buy a manual PBX anymore.

Quote
I'm trying to figure out which networking technologies would best meet most, if not all, of my requirements. My guess is it would be some technology that lies between separate regular landlines and PRI, if there is one. The PBXs that will actually be used are arbitrary and irrelevant, but they will all be analog and have no digital support.

Without digital support, you can only use standard POTS lines. Perhaps DID trunks are available somewhere still, but it is probably a long shot.  Most of them were provisioned with interoffice trunk facilities, I believe, which probably have all been replaced by fiber optics by now.

Quote
Is there a sort of medium between separate analog lines and PRI? I'm looking for a medium that will retain an analog transmission between the PBX and the Central Office, but the switching technology itself can obviously be digital (as all PABXs are).

I really don't understand what a middle ground (medium?) between analog and digital would be.  It can only be one or the other.
Analog carrier systems don't exist anymore in telephony, AFAIK.

Quote
Is there any way to maintain an analog connection between the central office and the PBX without running separate regular landlines for each trunk? Analog will be needed to support good call quality for regular analog rotary and pushbutton phones, fax machines, and modems (including dial-up). I want whatever trunk technology is used to function like a standalone line without actually being 4 or 6 separate standalone lines. Costs aside, my primary concern with having standalone lines will be direct inward dialing as well as direct outward dialing. Even if there are 50 stations, there are only a few numbers I'd want to have DID and DOD for - otherwise, I want only ONE telephone number - and NOT as many numbers as there are trunks (this might be appropriate for a Key Telephone System but not a PBX), since I want one number to be used for Caller ID from any non DOD phone, which I don't think standalone lines would support.

A common solution has been to use a SIP or MGCP media gateway with the required number of analog ports, and direct calls to the PSTN via these ports.  Media gateways, for example by AudioCodes or Mediatrix, were/are very popular to convert old PBXes with only analog facilities to use efficient trunking via IP networks.
This has been the recommended upgrade path even for vendors such as Lucent and Avaya, who both in fact certified AudioCodes gateways for such use. These are available in small boxes of 2, 4, 8, and 24 ports, but higher density carrier-grade equipment is available and very expensive.
Another possibility is the use of channel banks, such as by Adtran or Carrier Access.  In particular, I like the Carrier Access ADIT-600 boxes, because they have a VoIP access card that speaks the MGCP protocol for which I have written a protocol driver for Asterisk that works well.  The ADIT-600 provides me with 40 ports with local loop characteristics comparable to a standard POTS line.

Quote
If my internal extensions range from 1000 to 1500, the numbers I need supported for DID/DOD would be 1000 as well as a few other numbers between 1000 and 1200. I don't want to have to purchase a whole block of 200 "numbers" if that can be avoided (unless there is no additional cost).

I am estimating between 4 and 6 trunks will be required. Costs are not a concern, although since this will be installed in a home environment with 1 bill-payer, ideally they should be low.

Summary:

    No digital transmission (i.e. packet switching)
    Analog multiplexing is possible so multiplexing is fine if each individual circuit is analog.
    Routing as calls are dialed, not after
    Compatibility with DID and DOD

CLARIFICATION: I'm not asking anything about a PBX at all. I'm inquiring about the protocols used, specifically PRI, and if an analog variant of PRI (possibly a predecessor to PRI) exists."

Your equipment determines what kind of connectivity you need.  I would recommend building your private network first with the equipment you like and then look for outside access.  Start with a cheap SIP service that allows multiple calls, and an ATA, most likely it will be totally sufficient.

The idea of routing as digits are dialed went out the door long time ago, direct control was abandoned in the 1920s already in Panel offices. It is implemented in your equipment, not the network.   PS:   However, using MGCP digits can be transmitted one-by-one across an IP network. This does open some conveniences for switching to simulate old technology.  It is commonly deemed inefficient today, since the overhead for transmitting a single digit far exceeds (by factors of 100s) the payload of sending a single digit.  Nevertheless, MGCP was designed with a  decomposed network model by telecom people (Bellcore) with the traditional PSTN in mind.

The best quality is not with VoIP. The folks on networkengineering at StackExchange tried to convince me that digital was superior to analog too.
I'm definitely NOT using SIP. If I had to choose between PRI and SIP, I would choose PRI.

The PBX that would be used is completely arbitrary. This is something I would implement in about 10 years.

I would definitely want completely analog circuits WITHIN the PABX for sure. No reason to compromise on that there, since switching would be local.

I would have between 50 and 100 stations, in a private home environment. There might be a few other PABXs and PMBXs that are "stations" for this main PABX, and other phones would be connected to those nested PBXs.

I wouldn't need more than 4 to 6 outside lines - probably 10 is a maximum. This wouldn't be where I'm living now (Wisconsin) - it would be somewhere else, perhaps Montana.

The only reason I'd rather not have standalone analog landline connections for outside lines would be because EACH of the telephone lines would have their OWN number and there would be NO support for Direct Inward Dialing and Direct Outward Dialing. I'm not entirely sure by what is meant by "most people who refer to DID and DOD mean something else" - not sure what that something else might be but please enlighten me. I'm pretty sure I mean DID and DOD.

Let me explain:

For example's sake, Montana's area code is 406. So say I own a block of numbers in an exchange. Say (406) 255-XXXX. The XXXXs I want would be 1000 to 1500, let's say.

The main number I'd list in the telephone directory would be 1000, and it would have an auto-attendant. The numbers 1003, 1005, 1010, 1015, 1020, 1110, 1115, 1120, and a couple of numbers are numbers on which I'd WANT DID/DOD. So if I called (406) 255-1015, it would reach extension 1015. When these numbers dial out, their actual extension will be used for Caller ID (i.e. (406) 255-1015 if a call was made outside from that number).

But take extensions 1011 or 1111. These would NOT be DID/DOD, and these extensions CANNOT be reached DIRECTLY from the outside world. If an outside call is made using these numbers, the main number - 1000 - is used for Caller ID since there is no DOD - i.e. the caller ID for a call made from extension 1011 or 1111 would be (406) 255-1000

I have seen environments like this using VoIP/SIP - i.e. the secretary's number might be 2505 and the principal is 2510 and these numbers have DID/DOD, but calls can't be made to classroom phones from the outside, and calls made from classroom phones show up as 2500, not their internal extension number.

Hopefully I've explained well enough that you can get the general gist of it.

I want to use a medium to connect the main PBX to the Central Office that is as reliable and good-quality as individual analog, copper local loop landlines coming in.
But I don't want telephone NUMBERS for each Central Office line - they should all be equal in terms of what they can do, if that makes sense. A call to any number should be able to use any trunk, and the trunk itself will NOT have a number. Meaning the only number I'd "really" have would be (406) 255-1000, but there would be, say SIX "channels" or "lines" or whatever for that number meaning there can be 6 concurrent calls to that number, and with DID, the call will automatically go the appropriate extension - or the auto-attendant if 1000 is the actual number dialed.

Hope that makes more sense. I don't think the DID/DOD functionality I described can be accomplished with a bunch of individual standalone landlines, which is why I am looking for a single-cable solution that will support it. But that means going digital, which is not really a sacrifice I think I should have to make. SIP and VoIP are definitely not options and I will never use SIP/VoIP.

Well, sounds like you assume that you know more than the people you are asking advice from.
What is this objection against the standards of modern telephony based on, if not experience ?

Quote from: bellsystem on June 27, 2017, 02:28:53 PM
But that means going digital, which is not really a sacrifice I think I should have to make. SIP and VoIP are definitely not options and I will never use SIP/VoIP.

I have bad news for you.  Verizon is sending letters to large numbers of customers who have and have had for decades analog copper POTS service from them.  The letters inform them that within the coming year the copper outside plant will be retired and the customer must make an appointment to have a VoIP terminal adapter installed to continue service at the existing monthly rates.  This is not an attempt to raise monthly charges.

If Vz is doing this other ILECs surely are going to be doing it soon too if they aren't already.  The handwriting is on the wall.  Your choice will soon be to have VoIP service of some kind, cellular, or no service at all.  Take your choice.  Even if you get analog service installed you will be forced to migrate it.  Whether you like it or not, this is what's happening.

You can either give in or fight. I'm not a puppet that AT&T or Verizon can control. And it's not just me - see www.savelandlines.org

Anyways, I don't want to debate whether landlines are going away or not. I'd just like to know what options are available based on what I outlined. Even if what I'm looking for is deprecated, I'd still like to learn about it. Maybe I'll build my own central office :)

Quote from: bellsystem on June 27, 2017, 02:28:53 PM
The best quality is not with VoIP. The folks on networkengineering at StackExchange tried to convince me that digital was superior to analog too.

Well actually this is not so.  Polycom makes a series of SIP telephone sets which have much better than 3KHz BW and sound much better than a conventional telephone set.  Of course this benefit only accrues when two such sets are used end-to-end.

Carbon transmitters used in conventional passive telephone sets have very high inherent intermodulation distortion, so even an electret mike in a 3KHz circuit is vastly more natural sounding.

Quote from: bellsystem on June 27, 2017, 03:02:24 PM
You can either give in or fight. I'm not a puppet that AT&T or Verizon can control. And it's not just me - see www.savelandlines.org

Anyways, I don't want to debate whether landlines are going away or not. I'd just like to know what options are available based on what I outlined. Even if what I'm looking for is deprecated, I'd still like to learn about it. Maybe I'll build my own central office :)

You can build your own internal network.  Lots of people have.  You cannot create or recreate the network which serves the rest of the world beyond the confines of your property or your immediate contiguous neighbors.

Quote from: Alex G. Bell on June 27, 2017, 03:03:39 PM
Well actually this is not so.  Polycom makes a series of SIP telephone sets which have much better than 3KHz BW and sound much better than a conventional telephone set.  Of course this benefit only accrues when two such sets are used end-to-end.

Carbon transmitters used in conventional passive telephone sets have very high inherent intermodulation distortion, so even an electret mike in a 3KHz circuit is vastly more natural sounding.

AGB's advice is valid and correct.  High-bandwidth coders are becoming routine on VoIP systems today, especially within local networks.   But even on international calls to Europe I have routinely far better voice quality today using a commercial SIP network provider than I ever had with traditional circuit-switched telephony. 

Okay, I'm done debating voice quality. The reality is VoIP does not support many of the things analog lines do - like dial-up, DSL, fax machines, alarm systems, pacemakers, etc. Landlines are extremely versatile and can be used for many different purposes. Plus pulse dialing is supported, which, considering we're on classicrotaryphones.com, is very important!

Does anyone know what options I have for the scenario I have described? SIP and VoIP are out of the question. PRI would be my last resort.

Thank you all for your input!

Quote from: bellsystem on June 27, 2017, 03:02:24 PM
You can either give in or fight. I'm not a puppet that AT&T or Verizon can control. And it's not just me - see www.savelandlines.org

Anyways, I don't want to debate whether landlines are going away or not. I'd just like to know what options are available based on what I outlined. Even if what I'm looking for is deprecated, I'd still like to learn about it. Maybe I'll build my own central office :)

Well, have you read the nonsense on this page:  https://savelandlines.org/the-issues/  ?

Quote from: bellsystem on June 27, 2017, 03:15:21 PM
Okay, I'm done debating voice quality. The reality is VoIP does not support many of the things analog lines do - like dial-up, DSL, fax machines, alarm systems, pacemakers, etc. Landlines are extremely versatile and can be used for many different purposes. Plus pulse dialing is supported, which, considering we're on classicrotaryphones.com, is very important!

Does anyone know what options I have for the scenario I have described? SIP and VoIP are out of the question. PRI would be my last resort.

Thank you all for your input!

Oh, I'd say your options are approximately zero (give or take).  Since you don't have control over equipment deployed in the CO at the other end of the wished for transmission channel unless you establish yourself as a CLEC and rent co-location cage space, you are limited to those transmission methods chosen for deployment by the ILECs.  That topic has already been explored here pretty thoroughly.

A friend who has had a T1 delivering 6 true DID trunks and 800 PSTN numbers to him by a CLEC for the last 15 or so years is ready to bail and migrate to VoIP because of the ever mounting costs.  So if you're willing to "settle" for a PRI I trust that means you have deep pockets and cost is no object: a few hundred dollars/month is an acceptable cost.

Quote from: bellsystem on June 27, 2017, 03:15:21 PM
Okay, I'm done debating voice quality. The reality is VoIP does not support many of the things analog lines do - like dial-up, DSL, fax machines, alarm systems, pacemakers, etc. Landlines are extremely versatile and can be used for many different purposes. Plus pulse dialing is supported, which, considering we're on classicrotaryphones.com, is very important!

Does anyone know what options I have for the scenario I have described? SIP and VoIP are out of the question. PRI would be my last resort.

Thank you all for your input!

PRI is perhaps the last resort today.  But its days are numbered too. A high percentage of the business market has migrated to VoIP already.  In Europe the ISDN providers are terminating service arrangements already too.

The reality is that VoIP provides everything needed for modern communications, and that includes terminal adapters that provide a local loop as good as from a central office, only cheaper.

DSL is a digital transmission system over analog circuits, not needed anymore.  Fax machines work as well today over VoIP infrastructure, as before, but frankly why is it needed anymore ?
Land lines are extremely non-versatile in reality.  What other purposes might they be used for other than for analog telephone calls ?
Pulse dialing can be easily supported with cheap hardware.  Using pulse dialing on the network is completely unnecessary, especially as you are proposing to build some kind of local network with PBXes anyways.   PRI does not transmit pulse dialing either.

Being an activist for old technology is a waste of time.  Nobody listen to that stuff, and the market place moves forward.  It would be better to spend that time on mobilizing for better, modern, and more reliable infrastructure of the power grid, of transport systems, and such.  Why can't the power lines be as reliable today as dial tone has been for many decades.

VoIP does not work in a power outage. That is enough said. It isn't progress to me to move from something that will work indefinitely, like in the 1965 Blackout, to something that will shut off when it may be most needed. And dial tone is only getting less reliable as we move away from analog and copper. I'll take reliable over all the "cool digital features" any day.

Well, pulse dialing transmission to the Central Office is a must-have. So I guess PRI won't work for me really at all. I'm surprised even rotary telephone enthusiasts have no objection to the stuff that's happening right now. I'd at least thought that some people had avoided being brainwashed by corporate spokespeople...

Fax machines are necessary for legal documents. And if I want to fax something to someone, I have every right to do so. Back in the days of the Bell System, the telephone company worked for us. I'm disgusted how things work these days and how telecommunications corporations no longer look out for what their customers really need or want.

PS - power line faliures are common because of CASCADING failures, which is how many failures happen. That does not happen with telephone wires.

Quote from: unbeldi on June 27, 2017, 03:37:06 PM
Land lines are extremely non-versatile in reality.  What other purposes might they be used for other than for analog telephone calls ?

The one strength that they do have is that they work without local power.  AFAIK all VoIP solutions require the end user to provide power.  If commercial power fails, in an emergency it may be impossible to call for help.  Of course in a widespread emergency help may not be available anyway but in a local one it might well be.

The Vz letter about copper retirement says nothing about the customer needing to provide an AC outlet but does advise the customer to keep a spare "D" cell available to maintain operation during commercial power outages exceeding 24 hours. 

Their failure to advise customers of the need to provide an AC outlet is going to result in many Vz installers going out to migrate the service being unable to complete the task: a recipe of their own incompetent choosing for a huge waste of their manpower.

Quote from: Alex G. Bell on June 27, 2017, 03:48:35 PM
The one strength that they do have is that they work without local power.  AFAIK all VoIP solutions require the end user to provide power.

Certainly.  But they become useless too with the vast majority of telephone sets sold today that operate with a wall wart (and have no batteries), and go dead just the same as an IP phone or ATA.  Many cable Internet access providers supply cable modems or VoIP adapter with a battery backup. I got one in recent years that provided for 6 or 8 hours of backup power.

Well, all of the telephones I own now, and will ever own, will not require any power besides that supplied over the telephone line.

Say what you will, but it must be admitted that the older systems are better and more reliable for power outages and emergencies.

Quote from: unbeldi on June 27, 2017, 03:56:05 PM
Certainly.  But they become useless too with the vast majority of telephone sets sold today that operate with a wall wart (and have no batteries), and go dead just the same as an IP phone or ATA.  Many cable Internet access providers supply cable modems or VoIP adapter with a battery backup. I got one in recent years that provided for 6 or 8 hours of backup power.

The optical network termination equipment installed in multi-dwelling structures, such as by VZ in apartment building in cities, usually have local batteries installed to keep them operating for some time.

I think the subscription rate to fixed line services has dropped to below 40% of all subscribers in the US, so even with a land line in case of emergency, you can only call four out of ten destination anymore with your working land line.  And most of those are probably old folks that most young people don't want to call anyways.

Quote from: unbeldi on June 27, 2017, 03:56:05 PM
Certainly.  But they become useless too with the vast majority of telephone sets sold today that operate with a wall wart (and have no batteries), and go dead just the same as an IP phone or ATA.  Many cable Internet access providers supply cable modems or VoIP adapter with a battery backup. I got one in recent years that provided for 6 or 8 hours of backup power.

6-8 hours is almost nothing.  Even routine weather events in cold areas can produce outages much longer than that.  This is without considering rare events on the scale of Hurricane Sandy.  I know people who were without power for weeks as a result of that.  Living without heat, hot water or use of a stove you could still need to call for a medic or police.

Quote from: Alex G. Bell on June 27, 2017, 04:09:54 PM
6-8 hours is almost nothing.  Even routine weather events in cold areas can produce outages much longer than that.  This is without considering rare events on the scale of Hurricane Sandy.  I know people who were without power for weeks as a result of that.  Living without heat, hot water or use of a stove you could still need to call for a medic or police.

Well, it is somewhat of a hypothetical benefit.  Makes you feel good, or at least better. The people you most likely will call have dead iPhones by then.

The meaningful activity would be to advocate for reliable power systems.  Does it not seem inconceivable that mankind can send humans to Moon, and have robots operate on Mars for years and years, while being incapable of maintaining stable power in our cities ?   Where is a sense of  priority in that ?

Quote from: unbeldi on June 27, 2017, 04:03:32 PM
The optical network termination equipment installed in multi-dwelling structures, such as by VZ in apartment building in cities, usually have local batteries installed to keep them operating for some time.

Apparently not.  The copper retirement notice I saw was sent to someone in a 64 unit 13 story urban building.  If the ONT is going to be in the basement the customer would not need to provide access to a Vz installer nor keep a spare "D" cell handy.

Quote from: Alex G. Bell on June 27, 2017, 04:18:48 PM
Apparently not.  The copper retirement notice I saw was sent to someone in a 64 unit 13 story urban building.  If the ONT is going to be in the basement the customer would not need to provide access to a Vz installer nor keep a spare "D" cell handy.

Correct, the ONT units in the basement are not individual units for each apartment, but serve multiple customers each.  They should have some backup too.  I think, but I am not sure, some can also be powered via the fiber optic cable.   There are even optical power feeds where the termination device is powered by a high-power optical feed that is converted to electricity at the terminating end.

Quote from: unbeldi on June 27, 2017, 04:17:05 PM
Well, it is somewhat of a hypothetical benefit.  Makes you feel good, or at least better. The people you most likely will call have dead iPhones by then.

I don't see people being able to call 911 for a medic or police action as hypothetical.

Quote from: unbeldi on June 27, 2017, 04:17:05 PM
The meaningful activity would be to advocate for reliable power systems.  Does it not seem inconceivable that mankind can send humans to Moon, and have robots operate on Mars for years and years, while being incapable of maintaining stable power in our cities ?   Where is a sense of  priority in that ?

Theoretically possible but as with so many human endeavors, politics and conflicting interests get in the way.  Humans on the moon and robots on Mars?  Guys like Elon Musk are talking about establishing a human colony on Mars. 

Apparently the reliability of the power grid is far more precarious than in the past.  According to reliable sources the power grid is now very vulnerable to severe damage due to sabotage via the net than it was in 1966, 1978 and 2003 when large blackouts occurred just due to "ordinary causes".  It would take months to recover from such an outage due to lack of spare equipment and the disappearance of domestic manufacturers. 

With events such as the Wannacry worm and similar reports this very day reports about the vulnerability of the power grid hardly seem implausible.

Quote from: unbeldi on June 27, 2017, 04:27:51 PM
Correct, the ONT units in the basement are not individual units for each apartment, but serve multiple customers each.  They should have some backup too.  I think, but I am not sure, some can also be powered via the fiber optic cable.   There are even optical power feeds where the termination device is powered by a high-power optical feed that is converted to electricity at the terminating end.

That's the approach that seems intuitively obvious, technically feasible and a minimum requirement to meet public safety standards required in the past but apparently is not what they are doing, judging by the contents of the letter they are sending out.  This is not hearsay or innuendo.

Quote from: Alex G. Bell on June 27, 2017, 04:18:48 PM
Apparently not.  The copper retirement notice I saw was sent to someone in a 64 unit 13 story urban building.  If the ONT is going to be in the basement the customer would not need to provide access to a Vz installer nor keep a spare "D" cell handy.

I think I misread your statement.

I guess one has to examine what is installed in each situation.   The replacement system is adapted to the existing wiring in the building.  It may require installing local VDSL links for each customer from the basement.

Quote from: unbeldi on June 27, 2017, 04:34:32 PM
I think I misread your statement.

I guess one has to examine what is installed in each situation.   The replacement system is adapted to the existing wiring in the building.  It may require installing local VDSL links for each customer from the basement.

There certainly is already a pair from the basement to each unit so there is absolutely no technical obstacle to putting a common ONT in the basement.

Perhaps they are taking this much more costly and labor intensive approach so they have an excuse to wire the building for FIOS.  Perhaps they have scammed some PUCs to allow themselves to write off part of the FIOS wiring costs as part of a program to upgrade the voice network to fiber.

Many multi-unit buildings also use entry phone systems which intercept each unit's landline pair in the basement to provide direct access for visitors to call up a resident.  A single ONT in the basement would maintain compatibility with that widely deployed type of system.  An ATA in each unit would require an additional pair from the unit to the basement to back feed the ATA analog port to the basement "enterphone" system and back up to the unit.

QuoteWell, all of the telephones I own now, and will ever own, will not require any power besides that supplied over the telephone line.

I suspect that you will be a very lonely guy, in the future.  Have you ever heard the song "All alone, by the telephone." by Irving Berlin?

Since you are relatively new here, can you tell us a little about your experience in telephony? You seem to have the whole system figured out, and certainly know what you want, in technical terms. Are you a student of engineering? What types of phones and phone equipment do you collect or play with? You mentioned a future PBX. What do you see as your first system?  A step switch, crossbar, electronic, etc?

SxS (Strowger) switches are my favorite but it would not be practical for a primary PBX... it would be impossible to hook it up to the PSTN directly anyways,

So an electronic one. Currently, I have the Panasonic 308 and 824 analog PBXs with 4 rotary and 3 pushbutton phones. And in the process of collecting them, I managed to convince StopSmartMeters.org to collect about 60 telephones!

A common battery system is better. While a PBX makes the topic of a common battery kind of a N/A scenario, for homes with a single landline connected directly to the PSTN, common batteries are more feasible. They don't have to worry about anything.

Think about the things in your home with NO common battery. TV cable box. Modem. Router. The telephone is the only appliance with a common battery. And that is why uptime is 99.999%. Monopoly and centralization are more effective and efficient in the landline business.

Quote from: bellsystem on June 28, 2017, 06:05:34 AM
SxS (Strowger) switches are my favorite but it would not be practical for a primary PBX... it would be impossible to hook it up to the PSTN directly anyways

What makes you think so?  The dominant dial PBX technology in the Bell System and most everywhere else in the world from the 1920s through the 1980s, was some form of Strowger, before it was finally superseded by electronic systems, with some installations still in service into the 1990s. 

Many hobbyists have SXS dial PBX systems connected to the PSTN at this very moment, either by analog lines or by VoIP.  Some have crossbar as well or instead.  A few even have DID service.

REALLY?

I plan to have a few touchtone phones (because I have to) but I by far prefer rotary to TT.

If only there were a way to have the touch-tone phones on a separate PBX that worked together with the SxS switch.

I know it used to be dominant for half a century. I wish there will still some today in service commercially.

How would you accomplish DID with Strowger switches directly connected to the PSTN? I'm not into crossbar much because it doesn't have the same meaning to me as Strowger. I like seeing the switches move up and down. Crossbar to me is just kind of boring...

If this is accomplishable, I just might go that route! But I'm not sure how you would set it up. A SxS system is literally just switches. What would the outside lines each connect to. And when a phone dials 9, wouldn't they all attempt to reach the same phone?

To reach 911, I'd want to have to dial 9911, not 911, which would work just fine, but I'd like to be able to reach 90 by just dialing 0 - at least on the main PBX. I believe I could do this using call forwarding... except that's not supported using SxS.

That's why I was thinking of using an electronic system as my root PBX, and have several nested PBX - including a nice big SxS one. I don't foresee any problems with this - but maybe someone who has an SxS switch can comment?

I just don't understand how you can get DID/DOD with an SxS setup...

Quote from: bellsystem on June 28, 2017, 06:58:24 AM
REALLY?

...

I just don't understand how you can get DID/DOD with an SxS setup...

Yes. Hundreds of thousands, perhaps millions of Bell System PBX customers were served by SXS PBX plants.  DOD was a basic PBX feature starting in the 1920s, decades before DID was introduced in the late 1950s.

ANY SXS system consists of more than just switches.  Trunk circuits consisting of relays and transmission path coupling components are required between any two separate SXS exchanges.  Accordingly trunk circuits are required to interface a SXS PBX to the PSTN whether for DOD or DID.

Thousands of SXS PBX systems and millions of lines of SXS CO switching were converted to Touch Tone service starting in the early 1960s with the introduction of Touch Tone calling by adding Touch Tone converters which recognize dial pulses, store and outpulse the corresponding digits as a dial pulses at the slower DP rate.  Once an exchange is converted to TT operation rotary dial phones will continue to function on all lines.

There is much you will need to learn to understand how all this is possible and there is plenty of tutorial information available on line these days.  One basic point is that electronic technology does not make it possible to do things which were impossible with electro-mechanical technology because they were logically impossible.  This applies to such things as conflicting numbering plan objectives/requirements.

The smallest commercially mfd Bell System SXS PBX systems occupied a 24x36" footprint, standing 6½' tall, with 12 connecting paths and 50 station lines.  It's possible to construct much smaller ones if fewer simultaneous calls are required.  In addition to the 5 levels used for station lines, the upper 5 levels 6-0 were available for accessing various trunk groups (attendant switchboard, local CO trunks, tie trunks to other PBXs, WATS lines).

Wow, thanks!

Would you mind directing me to any diagrams or information about these systems online?

The thing is I would need * and # functionality on those TT phones (conference calls) so I would still need to get that to be able to work somehow.

Also, I would have a few key systems within the PBX.

Quote from: bellsystem on June 28, 2017, 07:52:07 AM
Wow, thanks!

Would you mind directing me to any diagrams or information about these systems online?

The thing is I would need * and # functionality on those TT phones (conference calls) so I would still need to get that to be able to work somehow.

Also, I would have a few key systems within the PBX.

Browse the TCI library at http://telephonecollectors.info/ & http://www.telephonecollectors.info/index.php/tci-library-inbox and use Google.

Don't get too far ahead of yourself with specific requirements.  When you are sufficiently up to speed you will understand what is feasible, what isn't and how to achieve the things which are.

But since you mentioned conference calls and since you are enamored of analog transmission, you should start off understanding its limitations:  To wit that conference calling is one function for which digital transmission is vastly superior and conventional 2-wire analog transmission is inherently deficient.  If you are diligent you will eventually understand why this is so.  The reasons are far beyond the time and space we have here.

The Bell System introduced 3-way calling for analog systems (even though it required a digital switch).

Just to make myself clear - I have nothing against digital SWITCHING. The PSTN is now 100% digitally switched. It's just the TRANSMISSION I'm concerned about.

Quote from: bellsystem on June 28, 2017, 08:48:55 AM
The Bell System introduced 3-way calling for analog systems (even though it required a digital switch).

Just to make myself clear - I have nothing against digital SWITCHING. The PSTN is now 100% digitally switched. It's just the TRANSMISSION I'm concerned about.

Just what sparks this concern ?   You express strong convictions, yet those concerns appear to be largely founded in ignorance, because you are asking questions one would expect researched and understood before raising concerns.

With the exception of the subscriber loop network, in countries like the US, transmission today is 100% digital too, and that started in the 1960s.

So far, analog has proven to be far more reliable in disasters and emergencies than digital.

The local loop is also critical as that is what allows for a common battery.

Quote"How would you accomplish DID with Strowger switches directly connected to the PSTN? I'm not into crossbar much because it doesn't have the same meaning to me as Strowger. I like seeing the switches move up and down.

"If this is accomplishable, I just might go that route! But I'm not sure how you would set it up. A SxS system is literally just switches. What would the outside lines each connect to. And when a phone dials 9, wouldn't they all attempt to reach the same phone?"

An SxS system is definitely NOT "literally [sic] just switches."  It is a power plant, battery string, alarm panels, tone and ringing supply, Line & Cut-off relays, Group relays, Line-finders, Selectors, Connectors, and the interconnecting wires.  Also, depending upon the needs of the subscribers, in real life, or YOU, as the Master of your own Telephone Universe, there will be direct-dial CO trunks, DID trunks, attendant trunks, (you WILL need an attendant position, right? A cord board goes nicely with an old Strowger, or you can upgrade to a console). There are central-office grade pulse-to-tone converters, and such eclectica as digit-absorbing selectors, selector/connectors, and party-line connectors.  The systems can be as simple or as complex as you need.

Are you familiar with the various clubs and organizations who perpetuate the history and study of telephony? I suggest you join ATCA, TCI, and sign up on the CKTS.INFO website as a member of the world's largest, international, privately-owned telephone system, called "C*NET".

Many of us own and operate electromechanical switching systems. Some of these are PAX's, some are PBX's, some are key systems, and some are relics of central office equipment of Strowger, X-Bar, panel, and various iterations of electronic systems. Some are home-brew ("Franken-switch") assemblages, some are straight out of the box key systems, and some are just a POTS telephone connected vial a simple ATA.

It is simplicity itself to arrange to have DID trunks, with PSTN numbers, connected to a genuine step switch.

On another note, I worked as a cable maintenance splicer in Western PA for many years.  I can assure you that in terms of system reliability, a damaged, wet, paper insulated, lead sheathed cable serving 900 to 1800 subscribers, can never be put back into service as quickly as a damaged optical fiber of the same "pair" count.

Victor, I joined this mailing list just last week: http://lists.ckts.info/mailman/listinfo/voip
Is that what you mean by "signing up?" There is no other sign up. I can't register since I have nothing to connect to the network.

Excellent. You will learn a lot from the members of that network.  There is expertise there that can never be duplicated.

Quote from: bellsystem on June 28, 2017, 08:48:55 AM
The Bell System introduced 3-way calling for analog systems (even though it required a digital switch).

Just to make myself clear - I have nothing against digital SWITCHING. The PSTN is now 100% digitally switched. It's just the TRANSMISSION I'm concerned about.

The Bell System introduced 3-way calling into CO switching systems with the No. 1 ESS, which was a stored program controlled (SPC) analog exchange using reed switches for the switching medium.  It was not a digital switch.

But the problem of providing usable conference facilities for multiple PSTN parties is very very different when the conferencing is performed at the CO than when it is performed on the customer's premises with additional voice frequency (VF) loss between each of the parties introduced by the loops between the CO and the premises where the conferencing is performed.

If you want to conference multiple parties on your premises that's a trivial matter.  PAX systems did that 100 years ago.  But this is lossy conferencing which is only satisfactory because there is no VF loop loss.  However I infer from your past statements that you want to conference multiple distant PSTN parties, not ones on your premises.

In many places, the Bell System stated about passive (analog) conferencing circuits located on the customer's premises with respect to conference calls which included more than one CO party: "transmission is not guaranteed", which is a way of saying that multiple distant CO parties may not be able to hear each other (due to the cumulative tandem circuit losses).

Quote from: bellsystem on June 28, 2017, 10:43:10 AM
So far, analog has proven to be far more reliable in disasters and emergencies than digital.

The local loop is also critical as that is what allows for a common battery.

You can have VoIP with 'common battery' using Power over Ethernet. You just need an 8-wire 'local loop'.

Every VoIP phone I use has had PoE (no other cords connected). But when mains power goes out, so does the phone.

Also, backup for these is more intensive since these phones use more power (often have displays, etc.) and power is going to unnecessarily go to every computer in the building, even though the computers shouldn't be run off of backup/emergency power.

And there's no COMMON battery for VoIP. I'm talking about power supplied by the central office.

BellSystem,

You're confused.  A PRI is the gold standard and offers the best sound quality between a PBX and Central Office, not analog.  Where did you get the impression that analog on the last mile, or space division analog switching is better in terms of sound?  It's absolutely not true.

Analog multiplexing.  Northern Telecom did have analog time division multiplexing in a PBX called SG-1, but it was inferior to digital time division multiplexing, SL-1.  The initial SL-1 telephones were analog to the PBX for voice, but digital for supervisory.  Time Compression Multiplexing is alternating half duplex mode of communication whereby each side transmits digitized signal at twice the speed only half the time.  The standard codec is lossy, but you can't tell.  You're using carbon microphones that are old.

I agree that VoIP is inferior in real world conditions, but it can work well in very small well managed and tightly controlled environment where the Ethernet network is voice only with excess capacity.  There are no queueing delays.

What are you trying to do?  Explain it, but keep it short.

ADID ... there are many ways of doing it -- DP, MF, DTMF, DISA ... COs like DMS are smart -- they can use DISA to do DID.

Rotary is supported on mine -- Option 11 with the proper variances which means 8 - 11 pps and a make/break ratio varying from x to y.  I have to look it up.

Our phones with screens and what have you will provide basic service during outages -- if you choose to use VoIP, there is PSTN fallback, but ... oh man, ... just explain you want.

It really depends on the PBX and CO you have, and what you're trying to do.  P

Quote from: bellsystem on June 28, 2017, 10:43:10 AM
So far, analog has proven to be far more reliable in disasters and emergencies than digital.

Digital 5ESS and DMS are way more reliable.  5E-XC is 6 9s and DMS-500 can do anything.

Quote from: bellsystem on June 26, 2017, 05:18:03 PM
I asked the following question on Stack Exchange but was told it was off-topic: https://networkengineering.stackexchange.com/questions/42193/pbx-co-trunks-analog-multiplexing-analog-version-of-pri

It's sort of technical in nature which is I presume why it was put on hold.

Does anyone know if they can maintain an analog connection between the central office and their house/business using just 1 cable, like PRI,  but with analog channels instead of digital? Is there a name for this type of technology to distinguish it from PRI?

I want the call quality and reliability of having as many separate landlines coming into the building as I needed outside lines, but the convenience that one large cable coming in offers - in addition to one cable, Direct Inward Dialing and Direct Outward Dialing are my primary concerns.

Nobody on the site I posted to was helpful, so thanks in advance to anyone who can help me out with this!


===========================================
EDIT: text copied from "other site" and pasted here for posterity


"PBX CO Trunks: Analog multiplexing (analog version of PRI)? [on hold]

I've been doing more research into PBXs, specifically trunk connection methods. My understanding is that there are 3 primary options:

    Separate telephone lines for each trunk line
    Primary Rate Interface (PRI)
    Session Initiation Protocol (SIP)

I'm trying to figure out what the best way would be to connect an analog-only PBX to the central office. I've already ruled SIP/VoIP out as being considerably inferior, from a quality and reliability perspective especially. PRI is preferable to SIP, but my understanding is that PRI uses TDM/digital transmission which would not be acceptable.

- - - - - - - - - - - - - - - - - - - - - - - - - -
Premise:

    Transmission must be analog, not digital, for call quality and reliability - the call quality should be basically the same as that with a separate standalone landline connection.

    Digits should be dialed immediately. I know many systems "hold" digits and then analyze the digits dialed using a "dial plan". Internally, this might be of some used. But if "9" is dialed for an outside line, I want the PBX to grab an outside line for the station and step out of the picture. The digits should be sent to the central office then as they are dialed, not all at the end (again, as with a separate, standalone landline connection).

    Going along with my second point, all central office connections, whether they are individual cables or one large one with separate analog channels, would have to be identical. Because the circuit will be grabbed as soon as "9" is dialed, all "features" (i.e. ability to make Long Distance/International calls) would have to be the same for each line/channel, since it would be impossible for the actual intended number to be analyzed. Basically, the call should be being routed as it is being dialed, not after.

    There's extreme controversy it seems regarding 9-1-1 and 9 9-1-1 going around (the linked petition will be impossible to force for systems such as the one I desire). I know that 9-1-1 will not be doing anything because to the central office, it looks like 1-1 has been dialed which could have easily been a switchhook mishap (I assume this is why 1-1 is not rerouted to 9-1-1). The PBX will be in a home environment (not a public system) and since I, most of the time, will be its only user, I will know to dial 9911 instead of 911 anyways. 911 should NOT connect to anything.

    I don't believe nesting PBXs will be a problem. I am going to buy a PBX that will support at least 50 stations, but one of the "stations" will end up being a corded switchboard PBX (PMBX or Private Manual Branch Exchange), and other "stations" may be other sub-PBXs that are PABXs, like the main one. Is there any way to use features like Direct Inward Dial from telephone stations to PBXs nested further down in the tree?
- - - - - - - - - - - - - - - - - - - - - - - - - -

I'm trying to figure out which networking technologies would best meet most, if not all, of my requirements. My guess is it would be some technology that lies between separate regular landlines and PRI, if there is one. The PBXs that will actually be used are arbitrary and irrelevant, but they will all be analog and have no digital support.

I believe something along the lines of an early 1970s analog PABX would end up being used (as is described here), but I am interested in what transmission technologies concerning the trunk lines should be used.

Is there a sort of medium between separate analog lines and PRI? I'm looking for a medium that will retain an analog transmission between the PBX and the Central Office, but the switching technology itself can obviously be digital (as all PABXs are). Is there any way to maintain an analog connection between the central office and the PBX without running separate regular landlines for each trunk? Analog will be needed to support good call quality for regular analog rotary and pushbutton phones, fax machines, and modems (including dial-up). I want whatever trunk technology is used to function like a standalone line without actually being 4 or 6 separate standalone lines. Costs aside, my primary concern with having standalone lines will be direct inward dialing as well as direct outward dialing. Even if there are 50 stations, there are only a few numbers I'd want to have DID and DOD for - otherwise, I want only ONE telephone number - and NOT as many numbers as there are trunks (this might be appropriate for a Key Telephone System but not a PBX), since I want one number to be used for Caller ID from any non DOD phone, which I don't think standalone lines would support.

If my internal extensions range from 1000 to 1500, the numbers I need supported for DID/DOD would be 1000 as well as a few other numbers between 1000 and 1200. I don't want to have to purchase a whole block of 200 "numbers" if that can be avoided (unless there is no additional cost).

I am estimating between 4 and 6 trunks will be required. Costs are not a concern, although since this will be installed in a home environment with 1 bill-payer, ideally they should be low.

Summary:

    No digital transmission (i.e. packet switching)
    Analog multiplexing is possible so multiplexing is fine if each individual circuit is analog.
    Routing as calls are dialed, not after
    Compatibility with DID and DOD

CLARIFICATION: I'm not asking anything about a PBX at all. I'm inquiring about the protocols used, specifically PRI, and if an analog variant of PRI (possibly a predecessor to PRI) exists."

I'm sorry, but you've misinformed people here, and seem to have a basic lack of understanding of DID, DOD, progressive vs. common control, TDM vs. packetized.

There is no analog PRI.  PBX trunks (analog) ... there are a zillion ways.  I imagine you want DP inpulsing. and not MF or DTMF.  There's ADID (inward), E&M.  Read Bellcore.  When I worked on DMS there lots of ways to do it, but PRI was better -- no glare, very quick setup and teardown.  PRIs are expensive.  If your PBX is analog only trunkside, what is it?  You can have analog lineside and PRI trunkside.

I have analog rotary/TT, TCM digital, UNIStim IP, ISDN stimulus mode lineside, and analog loop start, analog DID, PRI, SIP, and H323 trunkside.

A CO that's digital is not packet switched, it's time switched.  Your best trunk under real world conditions is PRI.  Forget about analog trunkside if you can get a PRI -- it supports everything.  Analog lineside is fine.

Switches are not progressive anymore -- translation.  It's transparent to your ear.

I'm not confused.

As long as the distortion introduced into analog transmissions is less than the loss of quality that is inherently going to be produced when a digital sampling is taken of sound, which is INHERENTLY ANALOG... then analog will be superior.

Sounds like everyone here is dissing analog because of DISTORTION and DISTORTION only.

Maybe someone in the PSTN should consider using SHIELDED cabling to minimize distortion. Shielded analog would definitely be better than digital.

As it stands, digital was introduced for long-distance mostly because of cost. It was so much cheaper than to use microwave radio relay and digital cabling for long-distance calls so one cable could have many calls going across it.

If we ignore cost and focus on the fundamental qualities of the two transmission methods, sound is NATURALLY ANALOG and will be closest to its purest form if KEPT analog. When sound is converted to digital and then back to analog, the actual audio/sounds that were produced at the other end are NOT reproduced accurately.

Quote from: bellsystem on June 28, 2017, 05:31:32 PM
I'm not confused.

As long as the distortion introduced into analog transmissions is less than the loss of quality that is inherently going to be produced when a digital sampling is taken of sound, which is INHERENTLY ANALOG... then analog will be superior.

Sounds like everyone here is dissing analog because of DISTORTION and DISTORTION only.

Maybe someone in the PSTN should consider using SHIELDED cabling to minimize distortion. Shielded analog would definitely be better than digital.

As it stands, digital was introduced for long-distance mostly because of cost. It was so much cheaper than to use microwave radio relay and digital cabling for long-distance calls so one cable could have many calls going across it.

If we ignore cost and focus on the fundamental qualities of the two transmission methods, sound is NATURALLY ANALOG and will be closest to its purest form if KEPT analog. When sound is converted to digital and then back to analog, the actual audio/sounds that were produced at the other end are NOT reproduced accurately.

This is rubbish.   

You might want to read the accounts of the technical problems that faced the engineers of the early transcontinental telephone lines, and study signal transmission theory, and the laws of digital information, of which the pioneers were also Bell System scientists.

Digital information is transmitted without alteration of information, otherwise facilities such as the World Wide Web via the Internet would hardly be possible.  Shannon's framework of digital information tells us that a signal can be completely and truthfully regenerated when it is sampled according to the sampling theorem.  This is implemented in digital telephony, which has a theoretical bandwidth of 4000 Hz.  But more recently, this has also been extended to provide much higher fidelity with HD voice.  In practice, even the more realistic band of ~3500 Hz pushes the capabilities of historical telephonic transmitters.  The response curves of various transducers are well known and available in Bell System records and other places.  Given theses limitations of the transducers, a telephone conversation cannot be transmitted with higher fidelity by analog means in practical circuits than with digital transmission.  It is the electro-mechanical transducers, receivers and transmitters, that limit the fidelity of reproduction, not digital transmission.  But digital transmission has other sources of distortion, but they can be fairly easily corrected, and is insignificant compared to analog signal distortions over distances typical in real-world situations.

Digital is not a truthful exact regeneration. By definition, as soon as something analog, like SOUND, is converted to DIGITAL, it is no longer the EXACT same sound wave (oh wait, it's not actually a sound wave at all).

In order for digital to be on par with analog when it comes to accuracy, distortions aside, the sampling rate would have to be INFINITY, which is, of course, impossible.
That's why analog is used. No such thing as sampling rates, since they're irrelevant. It's just a constant connection that literally transmits audio, not 1s and 0s of the audio.

Digital may sound better in the send in many cases but analog is a more ACCURATE reproduction of the original sound wave, since it IS that sound wave.

Quote from: bellsystem on June 28, 2017, 05:31:32 PM
I'm not confused.

As long as the distortion introduced into analog transmissions is less than the loss of quality that is inherently going to be produced when a digital sampling is taken of sound, which is INHERENTLY ANALOG... then analog will be superior.

Sounds like everyone here is dissing analog because of DISTORTION and DISTORTION only.

Maybe someone in the PSTN should consider using SHIELDED cabling to minimize distortion. Shielded analog would definitely be better than digital.

As it stands, digital was introduced for long-distance mostly because of cost. It was so much cheaper than to use microwave radio relay and digital cabling for long-distance calls so one cable could have many calls going across it.

If we ignore cost and focus on the fundamental qualities of the two transmission methods, sound is NATURALLY ANALOG and will be closest to its purest form if KEPT analog. When sound is converted to digital and then back to analog, the actual audio/sounds that were produced at the other end are NOT reproduced accurately.

You are referring to quantization error, not distortion.  I've done it.

DMS and 5ESS use PCM mu-law.  So, in DMS, we take 8000 14-bit samples per second, but we quantize down to 8 based on an analysis of speech.  You are using a carbon microphone (OLD) that produces 20% distortion by default in the analog domain.  Compare that to electret microphones.  We did side by side tests on so many people in the 80s with ePhone.  Night and day.

In theory yes, but, all analog transmission will pick up noise, like a vinyl record, along copper.  Analog modulation on fiberoptic lines would be immune however.  The problem is how do you switch.  You can't without degrading the signal.  Digital is immune because of error correction and interpolation  There are only two discrete states.  And, on long distance, you had to YELL, LOUD, when the system was all analog.  It was bad.  The switches couldn't do anything.  VoIP I don't like unless it's on a voice-only LAN and carefully done.

Digital Class 5 DMS came about not because of noise but because those SxS machines kept breaking down and jamming with all those moving parts, and were a maintenance nightmare -- 5XB wasn't quite as bad, but still a pain.  Crosstalk, clacking relays -- come on.  Now, DMS and 5ESS come along and there are almost no moving parts, and then D evolved to become a single stage time switch -- non-blocking.  100% of the switching fabric could be used, vs. 10% on SxS.

All DMS did was read out numbers in a different order than they were read in, and the position determined the trunk, and so on, through a big glob of memory.  It was a sorting machine that blew people away.

We did a lot of work on analog.  The last mile is analog because of distance.   If you want all analog, you can do it.  I convert digital to analog, IP to analog, the other way around, but you need incoming only and outgoing only without E&M, and you don't have DISA DID.

The PSTN isn't even TDM anymore -- the periphery is, but the core is optical Ethernet.

Guys, this conversation is way over most of our heads.  It's certainly over mine.  This thread is not something that I would normally follow.  I don't have the time to read every thread on the forum.  I was alerted by a moderator that this was "heating up" so I have picked my way through it.  Let's keep it civil please.

You all feel free to continue.  But please keep personal remarks and other possible inflammatory comments off the forum.

Thank you.

~Dennis

I agree with Dennis,

Most of the replies I have been receiving are "technical" explanations about why digital is so great and analog sucks or personal attacks on my telephone preferences,

To be clear, what I want to know is purely academic. I never said I would plan to implement a system. I simply want to know if such a system exists, how it works, and how it would differ from PRI and standalone analog landlines.

Rather than inserting your own opinions into answers to the point where I can't distinguish facts from opinion, I would appreciate it if I could get a facts-only answers that just lays it on thick. If nobody knows, that's fine. I'm only half-sure of what I'm asking myself.

Also, to Dominick: So, in DMS, we take 8000 14-bit samples per second, but we quantize down to 8 based on an analysis of speech.
What if you're not sending speech? How about music? That's likely to lose some of its richness when sent digitally.

And if I may ask, if carbon transmitters are so primitive, then why do they sound better than pretty much any cell phone or VoIP phone? I haven't used a digital phone that isn't VoIP, so I can't compare. But I do own 7 telephones right now - 5 of which have carbon transmitters. The two that do not are relatively new and are electronic phones - an AT&T 100 and a Panasonic programming unit. The Panasonic phone sucks. Tons of static, totally unusable, except for Caller ID. The AT&T phone is so soft, you can't hear the dial tone unless you jam it into your head. The voice quality on one of my Western Electric 500s is ten or twenty times better, easily, than my non carbon-transmitter phones. Then again, these are all connected to Panasonic electronic modular switching systems, which are digital. But transmission is analog.

Also, calls on Panasonic PBXs ARE routed as they are dialed. If I dial 9, I hear another dial tone. On VoIP phones or probably most other PBXs today, VoIP or not, you don't hear another dial tone after dialing 9. If someone could explain how NOT routing the call as it is dialed is supposed to make the call route faster, that would be much appreciated. I have 2 PBXs tied to each other, rather than to any Central Office lines, and if I keep going back and forth again, the delay tends to get longer and longer (i.e. ringing, stop ringing). Not sure if that is related to this somehow.


Finally, can people have their own Central Office, either for collecting's sake or to do things the way they want? How would that all work, as far as connecting it with the rest of the PSTN?
If you have your own Central Office, can it be private? Or does it have to be available for public use?


Thanks all!

The traditional common battery central office arrangement has been replaced, over the last 30 years or so, in rural areas that are becoming suburbanized, with pair-gain equipment, powered by commercial juice, with back-up batteries. There are probably fewer continuous copper lines in service right now in RBOC's as there are lines that are not directly powered by the battery in a central office.

To echo Dennis: this is a topic well over my understanding, Im simply a collector and not an engineer by any means....BUT... just my two cents from a simple mind....

I understand the debate between digital/landline (analog) systems regarding transmission etc, however I think we are missing a few key points (but hey, I could be wrong....)

Cell phones generally have many microphones arranged around the edge of the device to better pick up voice. Lets face it, these "smart phones" are less than ergonomic. A G-3 handset is self aligning for optimal voice transmission, i-phones, not so much. So the designers took the liberty to improve the odds in their favor. As a result you tend to pick up a lot of ambient sounds and the like. Calling is also almost seen as a secondary or tertiary function of these devices. "Browsing", imaging, and apps are likely the largest responsibility of a modern smart phone vs calling (ask a high-schooler how much they actually call their friends vs snapchat or other apps). So a network to handle all that sort of data simply needs to function differently than the days of Ma Bell.

Moving on.... transmit/receive characteristics for cell vs a landline aside, at some point they all end up hitting the airwaves (AT&T Long Lines?) and or a satellite blinking overhead. IMO a purely copper system has not existed for some time, especially concerning long distance calls. These moves to digital (cordless) have been in place since the 30s with "portable" radio phones.

You can create your own network however, its more of a PBX system though in all actuality. I wont even try to explain all that, there are experts in that dept all over CRPF. Additionally you can also look into C-net. Yes, it uses the internet as a means of transmission, but it comes fairly close to replicating an analog system in terms of the switching gear and so on (could also be wrong about that...)

Landlines and payphones are dying off quickly and it is sad to see. However (and it pains me to see it), such was the fate of steam locomotives, VHS, etc. Money drives the world, faster, cheaper, "better" is always going to be out the old reliable vanguards of the prior generations.

Well thats my rant.... Im going to go hug my WE 302 thats on my desk to cheer myself up....
 

BellSystem,

The PSTN was never designed to transmit CD quality audio when it was analog.

If DMS will accept a candlestick with no dial and you can just say who you want, why would you not like that?  It could any kind of ringing, was very forgiving on slow dials.  We had rotary phones that dialed at 20 pulses per second.  We could dial by saying "Sara, get me Doc Stewart".  This was speaker independent speech activated intelligent dialing.  Implicit SAID.  It would even remove dial tone and you would get that 1920 experience.  Your SxS can't do that.  We used to set it up so that we had every phone from a dial-less candlestick to rotary to touch tone to ISDN (EKTS) to Centrex EBS or ISDN to Centrex IP phones.  It was magical -- all these phones from different eras could call each other.  Toss in 1A2, sure.

What is the PSTN?

The PSTN was Aggregated Digital Time Division Multiplexing via
Synchronous Optical Networking (SONET - Optical Carriers OC-3 thru OC-192), and later
Asynchronous Transfer Mode (ATM)

Now, the core is Optical Ethernet (Dense Wave Division Multiplexing) while the periphery is still TDM in many places.

5ESS and DMS are TDM.  4ESS down to 1A and 1ESS no longer exist, sadly.  DMS took on the role of 4ESS.

5ESS, 5E-XC, DMS-10, 100, 200, 250, 300, 500, CS1500, CS2000, CS2100 (Military) and all the remotes 10 years ago were there.  It's changed quite a bit.

Now it's mostly MPLS/IP.  Everything keeps changing.

Didn't you know?  It's not analog except on the last mile and it changed from circuit to packet gradually over the last 10 years.

DMS has DWS (Dialable Wideband Service).  Others call it Switched Fractional or Multi-Rate ISDN.

This allows us to take a PRI which is 24 channels, each channel capable of 64 kilobits/sec,
and bonding 2 to 24 of them for any call.

Two calls using 12 bonded channels would do it.  How?

A compact disc stereo channel is 44,100 samples per second x 16 bits/sample = 705,600 bits per second

1/2 a PRI (12 channels) x 64 x 1024 = 786,432 bits per second will carry STEREO LEFT
1/2 a PRI (12 channels) x 64 x 1024 = 786,432 bits per second will carry STEREO RIGHT

Each call only needs 705,600 bits per second of the 786,432 available.

Analog systems cannot transmit with this fidelity.  You couldn't do this with an ordinary telephone.  Special equipment is required, similar to the stuff for video broadcast over the PSTN.  Video used this all the time before 1MMS came out.  It's wasn't packet -- it's circuit.  You dialed a phone number, but we had special equipment for it.

DMS is carrying the data RAW in DWS, so CPEs on either end handle the rest, because a telephone's microphone cannot transmit frequencies as high as 20,000 Hz.

Carbon microphones produce distortion -- we measured it at 20%, whereas electret was almost nothing.  This is the actual telephone.  Then we put the digital converters in the phones, and we used something called TCM ping pong.  Each caller transmits at twice the normal the speed but only half the time.

There's no problem with SONET or ATM or T1 or whatever.  I don't understand what your concern is, because SONET and ATM are dead, and have been replaced by Dense Wave Division Muliplexing Optical Ethernet.

Are you not aware the PSTN is fiber -- my brother and I can show you.  It's all optical trunking between switches.  You have copper twisted pair going in, and that can be analog or T1, or PRI, or ISDN BRI.  There are packet gateways too, cellular as well.

AT&T's backbone was 40 gigabit IP/MPLS several years ago.  Dunno what it is now.

If you want your own circuit-switched central office with battery, I would suggest an Option 11 PBX with analog line cards and it has battery backup, will accept rotary dial, digitone, Autovon, ISDN ksets, and Meridian phones.  It will satisfy your needs.  Very nice small switch.  You can do 7 digit dialing, and you can use the Universal Analog Trunk Card, although I recommend the PRI.

You'll have fun.  I did, because the like the old and the new.  I don't like what's happening now, because our Bible was not to desupport rotary.  We still had 10 party service coding, 4 party, 2 party ... any scenario you wanted was possible.

I can't think of any analog electromechanical switches that can act like a CO that aren't huge.  SF 1 is still big.  Long gone.  There you have it.

I'm having fun with you but everything above is true.  You've just been misinformed.

If people don't understand this, maybe they should learn, or complain to the FCC and CRTC.

TDM was fully backward compatible and even offered 10 party line service.  Geez, you could use a candlestick phone with no dial on it.  How can you not like that?

DMS would even take away the dial tone, you just had to say "Sara, get me Doc. Stewart".  You'd have to record that as voice print in advance.  We called it SAID.  The cutest thing.

It was a modern machine that supported every phone ever built.  I loved that thing

BellSystem ... listen I don't want to argue but when we switched to electret people were used to the distortion of carbon and it sounded weird to them.  It's not richer, trust me.  It's what you're used to, and analog created a lot of problems -- crosstalk, and it didn't do well over long distances.

I understand why you feel the way you do, but I don't like VoIP, because it is inferior, but digital is not at that sampling because we only had 16 bit chips back then, and mics where #### anyway.  The processor was only 36 MHz.  We went electret in 1983 ... yeah, it was then.

QuoteIf you want your own circuit-switched central office with battery, I would suggest an Option 11 PBX with analog line cards and it has battery backup, will accept rotary dial, digitone, Autovon, ISDN ksets, and Meridian phones.  It will satisfy your needs.  Very nice small switch.  You can do 7 digit dialing, and you can use the Universal Analog Trunk Card, although I recommend the PRI.

So what's the difference between Universal Analog Trunk Card and PRI as far as features?

Can Analog support Direct Inward Dialing? I know PRI can.

I've seen a video of a guy who has his own small SxS central office. Can I just build my own central offices, connect my PBX to it however the heck I want to, and then connect the Central Office to other Central Offices? Could it be a private CO, or would I have to connect subscribers who wish to be connected?

Quote from: bellsystem on June 28, 2017, 07:13:36 PM
Digital is not a truthful exact regeneration. By definition, as soon as something analog, like SOUND, is converted to DIGITAL, it is no longer the EXACT same sound wave (oh wait, it's not actually a sound wave at all).

Why don't you show us where your 'definition' is written.  Show us that Shannon's theory of information transmission is wrong, and backup your story with sources.

Shannon showed us that ALL communication is essentially digital. This is a fundamental precept of modern communication. It is something that nobody has argued much anymore for close to 70 years.   Your level of belief is that of the 1940s at best, and it is only belief, not science.  Without Shannon's recognitions, communication would have been at a standstill, without T1, TDM, fiber optics, all the technologies Dominic showered you with, and without the Internet.

Quote
In order for digital to be on par with analog when it comes to accuracy, distortions aside, the sampling rate would have to be INFINITY, which is, of course, impossible.
That's why analog is used. No such thing as sampling rates, since they're irrelevant. It's just a constant connection that literally transmits audio, not 1s and 0s of the audio.

Digital may sound better in the send in many cases but analog is a more ACCURATE reproduction of the original sound wave, since it IS that sound wave.

Isn't that a circular contradiction?  How can something sound better but be less accurate when it is the message that is important.

Analog transmission is in fact NOT used as a rule.  The fact that the last-mile network is still analog is purely historical and reflects more local economics and politics than science and technology. It certainly has nothing to do with quality, fidelity, or similar notions.  The last mile is about the best we can do with a modern level of quality in analog transmission.

EVERY communication system has to make compromises between physics, economics, and policy or politics.  Your ideas about infinite sampling rates to achieve analog quality is simply wrong, because no transmission channel exists that has infinite bandwidth, that can transmit messages without loss or distortion.  A perfect channel is exactly as impossible as an infinite sampling rate.

If that weren't the case, then we never needed telephony, and in 1915, Alexander Graham Bell in New York City could have simply spoken to Watson in San Francisco directly, without the first transcontinental line and no telephone.  But as we know, this method already fails across a busy mid-town NYC avenue. Despite human's considerable intelligence, the brain cannot discriminate against all that noise. The same happens in an analog communication channel, no matter what its bandwidth is.  In fact, we do better with less bandwidth because we know that the crucial message extends only from 300 to 3000 Hz, and predominantly even less. Thus we can simply sample that message at a rate of twice its highest frequency and truthfully reproduce it at the other end of a digital communication channel.


I think it would behoove you to take in the advice you get here on the Forum and take it a starting point for your own research and not contradict immediately with ill-founded notions.  You have already heard from people with exceptional expertise in telephony and its history.  Some of the members here have built and maintained central offices professionally, some have built entire offices in their spare time for fun, and many have equipment in their collections that rivals or exceeds any technology museum.  If this many people contradict your views in such a short time, you might want to rethink your positions rather than dig in, and do some studying on your own to familiarize yourself, or to find well-founded arguments against those contributions.  Telecommunications is an immense field and not everyone is expert in all areas, but contributions here are always intended to help, rarely for self-promotion.

Quote from: unbeldi on June 29, 2017, 10:09:46 AMEVERY communication system has to make compromises between physics, economics, and policy or politics.  Your ideas about infinite sampling rates to achieve analog quality is simply wrong, because no transmission channel exists that has infinite bandwidth, that can transmit messages without loss or distortion.  A perfect channel is exactly as impossible as an infinite sampling rate.

OTOH, even if infinite sampling rates could be accomplished it would be pointless since human hearing is far from having infinite bandwidth either.  It is pointless to transmit signals which cannot be perceived at the receiving end.

Motion pictures or videos of which B-S is so fond are sampled data streams too but they are perceived as continuous motion as long as the frame rate exceeds to persistence of the eye and central nervous system.

Sound is not inherently digital. So as soon as sound is converted to digital, it is not longer an exact replica of that sound, like analog is UNTIL distortion gets introduced.
(Even this basic website says that the human voice is analog, if you don't believe me: http://www.diffen.com/difference/Analog_vs_Digital)

If, in a perfect world, analog systems were distortion-free and didn't suffer from distance degradation, analog would always sound better than digital.

Finally, here's something to read from HowStuffWorks: http://electronics.howstuffworks.com/digital-versus-analog.htm/printable

Here's a quote:
Some audiophiles argue that because analog recording methods are continuous, they are better at capturing a true representation of sound. Digital recordings can miss subtle nuances. But as digital recording processes improve, digital devices can use higher sampling rates with greater precision. Although the signal still isn't continuous, the high sampling rate can create a sound similar to the original source.

Before the 1970s, musicians recorded their performances on analog recording equipment. Microphones recording the sound generated an analog wave that other devices would then transfer directly to the proper media (usually magnetic tape). Assuming the recording artist used reliable equipment, the sound recorded was an accurate representation of the original sound.

Any time engineers have to convert a recording from one format to another, there's a chance that the quality will suffer.

Paragraph 1 from HowStuffWorks says that analog recording is continuous and can more accurately capture the true sound. It's basically the equivalent of infinite sampling rates, which is impossible. No matter how high the sampling rate for digital recording is, it will always miss something(s) every single second. The difference may be completely negligible, but it, from a technical standpoint, exists.
Paragraph 2 says if the equipment is reliable, then the recorded sound is an accurate representation.
Paragraph 3: The human voice is naturally analog. So when it is converted to digital, there is a chance quality will suffer.

The major drawbacks of analog in the PSTN are for long-distances. These "disadvantages" don't really exist if you call a telephone in the next room. Analog transmission travels at the speed of light, while digital transmissions are always subject to any delay introduced by the computers that process the signals. That's why VoIP is sometimes so choppy - often not all the packets even make it to their destination. Even with non-VoIP digital systems, it's not as instantaneous.

The article IS mostly about audio recording, not telephony, but the same principles apply.

Again, what is to all of you if I stick myself with "inferior" equipment. I'm not asking anyone else to use analog transmission mediums.

Quote from: bellsystem on June 29, 2017, 09:38:08 AM

Can Analog support Direct Inward Dialing? I know PRI can.

DID is not a technology that is bound to any particular method of transmission.  It is rather more of a methodology of routing and signaling of telephone calls.  It is essentially a trunking method to a private branch exchange and has been implemented on analog trunks as well as digital multiplexed circuits.  It is a method to minimize the cost of multiple communication channels w/r/t the actually anticipated need of multiple simultaneous channels during peak traffic hours.  During each call setup, the central office sends the destination address information via the trunk.  On analog circuits that can be DTMF or pulse dialing, on digital circuits it could be DTMF or any other digital message format, for example using RFC 4733 named telephony events as RTP payload.

While probably still available as a facility on 5ESS and DMS systems, you might be hard-pressed to find analog DID trunks at reasonable cost today. A fractional T1/PRI circuit was already cheaper some 10 years ago or so, IIRC, when you consider all costs involved.  It depends on the scale you are looking at, there is a cross-over point for cost vs capacity that has constantly been changing with resellers and time.

And for the "reliability purist" in you: Don't expect to power your equipment from the analog DID circuit either, it does not provide battery.
Of course, your PRI line will also go down if you don't take care of your own power on your end.

Thanks,
I am well aware that phones on a PBX do not use the common battery from the central office. Their common battery is the PBX, and the PBX must have adequate backup power. But as long as the PBX has backup power/generators/etc., the lines from the Central Office will still work.

I'm not too concerned, but does there exist a case where analog DID trunks are cheaper than T1/PRI?

I'd also need DOD (Direct Outward Dialing), for the same extensions that DID is used on. Is that supported on analog trunks?

I did some research last night. Apparently, with analog trunks, Caller ID is not provided until after the first ring, whereas with PRI, it is provided instantly. This wouldn't be a big issue for me, seeing as how none of my phones will be able to display Caller ID anyways... but is this due to some inherent limitation of an analog trunk?

I looked up the 5ESS and DMS100. The descriptions all say they are TDM systems. Can they be configured to analog switching?

Quote from: unbeldi on June 29, 2017, 10:55:48 AM
It is a method to minimize the cost of multiple communication channels w/r/t the actually anticipated need of multiple simultaneous channels during peak traffic hours.

Not exactly.  DID was introduced in the Bell System on SXS PBXs circa 1959 with DuPont in DE.  It's written up in an AIEE article authored by a BTL PBX developer. 

DID trunk groups supplanted ordinary PBX trunk groups, reducing the number of attendants required to complete or transfer calls which reached the wrong extension.  Calls to the LDN (listed directory number for the company) also complete over the same trunk group.  So the number of trunks required from the CO to the PBX is not changed by the introduction of DID.

However DID is described in Harry Hershey's 1917 book.  In a direct control SXS CO environment it was always possible to integrate a customer premises dial PBX into the public exchange numbering plan.  However in those days there was no DDD, the majority of phones were manual, so as the Bell System converted to dial, first using common control Panel machine switching, they made no provision to pass stored customer dialed digits into a dial PBX even connected to the same Panel Office.  This was perpetuated in #1XB and #5XB.  Even as they used SXS in some medium size cities they chose not to offer DID service in those places. 

Finally when they implemented Line Link Pulsinng in #5XB, allowing a Dial Pulse Sender, which ordinarily sends digits out on trunks to other COs, to send them on lines to a customer PBX, DID became possible. 

So their choosing to not offer DID even in cities served by SXS CO equipment must have been a business decision more than a technical driven one.  Perhaps they choice that because they did not want to create a demand for service and pressure on themselves to modify the equipment serving larger cities to provide DID there too, although clearly once they decided that it was a service they could tariff and offer at a profit, they reversed that decision.

As an aside, they used DID for "official PBXs" (PBXs serving Bell System employees) well before they offered it to commercial customers.  This is true of many systems and service features they introduced to the public: they developed them and used them internally years before offering them to the public.

I think I kept my DID summary as short as possible.  When involved, attendants should certainly also be considered part of a communication channel.  Attendants and their jacks, plugs, cords, and keys were the forerunners of silicon chips.

So, are there Central Office solutions (even if it requires me to build my own CO) that would allow analog PBX trunks that support both DID and DOD?

Quote from: unbeldi on June 29, 2017, 11:31:22 AM
I think I kept my DID summary as short as possible.  When involved, attendants should certainly also be considered part of a communication channel.  Attendants and their jacks, plugs, cords, and keys were the forerunners of silicon chips.

The point is that DID did not reduce the number of channels required between the PSTN and the PBX.  Both the DID traffic and attendant traffic was usually carried over a DID trunk group of the same size as the previous incoming ringdown trunk group which appeared only at the attendant.

I never said DID reduced the number of trunks needed. It just reduced the need for a PBX switchboard operator to manually transfer calls to their destination.

Quote from: bellsystem on June 29, 2017, 11:34:52 AM
So, are there Central Office solutions (even if it requires me to build my own CO) that would allow analog PBX trunks that support both DID and DOD?

Trunk tables showing the available types for the widely deployed 701B SXS PBX list 2-way DID trunks allowing both DID and DOD service on a single trunk but I don't know whether any BOCs tariffed them. 

Pacific Bell told me that 2-way DID trunks were only available on T1 "because it is logically impossible".  Of course if it were logically impossible it would be impossible on a T1 also.  Essentially a 2-way DID/DOD trunk is technically no different from a 2-way loop signaling interoffice trunk, millions of which were deployed throughout the world.  The difference is that the exchange at one end is privately owned rather than both ends terminating at a Telco exchange. 

The fact that it was shown in the AT&T-published 701B trunk tables also demonstrates that it was not logically impossible at all.  (Just one of many examples of strongly held misinformation from my Pac Bell service rep.)  A T1 would have been cost prohibitive.

Quote from: bellsystem on June 29, 2017, 11:42:06 AM
I never said DID reduced the number of trunks needed. It just reduced the need for a PBX switchboard operator to manually transfer calls to their destination.

And I never said you did.  I said unbeldi did.  You need to read more carefully before replying.

Given that I can't use touchtone telephones with an SxS office, is there an electronic switching system that will allow for analog DID/DOD?

As a moderator I cringed a few times reading this hoping that no hostilities would break out and they didn't. Great discussion everyone.

Terry

Quote from: bellsystem on June 29, 2017, 12:01:59 PM
Given that I can't use touchtone telephones with an SxS office, is there an electronic switching system that will allow for analog DID/DOD?

Once again you are not reading carefully or not absorbing what people write.  I stated explicitly at least once, perhaps multiple times, that SXS PBXs were converted to TT service.

Please read more carefully and avoid repeating questions which have already been answered.

Alex,
How can one use the # and * keys when connected to a SxS switch? Even if there were a converter at the end that converter tones to pulses, it can't convert the # and * into anything recognizable. Plus, the whole point of touchtone dialing was to speed up dialing. I'd much rather use a rotary phone than a pushbutton phone that is effectively pulse dialing (I'd rather use a rotary phone anyways though!).

Quote from: bellsystem on June 29, 2017, 12:17:26 PM
Alex,
How can one use the # and * keys when connected to a SxS switch? Even if there were a converter at the end that converter tones to pulses, it can't convert the # and * into anything recognizable.

It depends on what you want to do with them, which you have not stated.  Or perhaps it was lost in the reams of verbiage.

Quote from: bellsystem on June 29, 2017, 12:17:26 PM
Plus, the whole point of touchtone dialing was to speed up dialing. I'd much rather use a rotary phone than a pushbutton phone that is effectively pulse dialing (I'd rather use a rotary phone anyways though!).

In fact a TT/DP converter is FASTER than using a rotary dial because no time is lost winding up a dial (approx. 1 second per digit since human reaction time is a significant fraction of a second) and because "machine sent" DP minimizes the pauses between digits.

::) You can't have it both ways.  You rejected crossbar because you like to watch SXS switches.  I guess your mission will be to reinvent SXS switches which go directly to the required level without stepping through the lower ones in response to TT dial signals.   ;D

Alex,
I think you midunderstood,

I DO want a SxS switch. But not as my MAIN PBX. I will nest that as a station. So to make an outside call with that, I would dial 99 first. I plan to have multiple nested PBXs, including PABXs and PMBXs,

My primary PBX will definitely be electronic. So will the central office it is connected to, although if I have my own Central Office, I might also offer connections to that. While I definitely want the great technology of the 20s, I also need the boring technology of today in order to join conference calls and navigate IVR systems.

I want to be able to use TT phones just as one would expect in 2017. The SxS switches I have will serve more of a hobbyist purpose rather than a functional one.

Sorry for any confusion. My main PBX will definitely be 100% electronic and it will definitely switch internal calls analog - and hopefully CO ones too.

Quote from: Alex G. Bell on June 29, 2017, 11:39:43 AM
The point is that DID did not reduce the number of channels required between the PSTN and the PBX.  Both the DID traffic and attendant traffic was usually carried over a DID trunk group of the same size as the previous incoming ringdown trunk group which appeared only at the attendant.

That is only because the number of circuits was already optimized based on peak traffic analysis. This was well practiced for a long time.  DID added the capability for direct addressing of stations without providing a dedicated ringdown circuit for each, which was not possible previously and would have required expanding a ringdown trunk group. DID therefore indeed minimized the cost ratio per benefit, if not the absolute cost or number of circuits.

But this level of detail and bickering is rather inappropriate in the scope of the thread and the level of questioning by the OP.  At some point you have to be able to decide to stop explaining and complaining over every ever so minute detail and move on.

PRI has faster call set up and tear down and resolves glare with DMS automatically.  I have a Central Office Simulator too, but that's no fun.

There are/were NI-1, NI-2, DMS-CUSTOM, and 5ESS flavors of PRI.  We had our own custom PRI format because we felt the standard and 5ESS formats were suboptimal (ie. sucked beans), but, we respected 5ESS, and supported it fully so that we could communicate with it and all Western E. equipment.  You're DMS?  I thought we were talking to a 5ESS or 5XB ... fooled ya, didn't we?  The joke's on you!  Listen for a clean dial tone next time pal and no CLUNK.

I have analog direct inward dial on my Nortel BCM 50 PBX via an ADID-8 media bay module.  Nobody offers it, even though DMS can do it.  I dropped verbal F bombs on Bell when they said no.  They wouldn't offer fractional PRI ... more yelling.  I'm not paying for no effin full PRI ... gimmie 4 channels and shut your face.  Oh, and I want a Meridian Centrex EBS analog line too (the 8 kHz one) and an ISDN BRI digital with EKTS (Electronic Key Telephone Service) and CACH (Call Appearance Call Handling) ... more NOs.  Well ef u then.  LOL.

As a fully digital single stage time switch, no analog device or PBX or party line was left out.  All were welcome ... including all pay telephones.  As a computer, we could do more than SxS or crossbar.

"Bell, I want LRS (line reversal on seizure)" ... no.  But this analog thing needs it.  No.
"Bell, I want LRA (line reversal on answer)" ... no.  Same as above.

Go into DMS and ADO them through SERVORD and never say that again, or I'll out all your DNs so fast you'll have to use string and paper cups to make calls.

Grandfathered?  DMS still accepts those commands.  I'll grandfather you if you don't stop this nonsense.

THEN, they replaced DMS with a copper line gateway to a BROADWORKS softswitch and pulse service was gone.  "Bell Canada, you will live to regret this moment".  LOL.

We learned from ESS and developed SP-1, but then said, oh, let's just make the whole thing digital.  It was the logical next step.  Your ear is not capable of discerning the difference BellSystem.  Only Lindsay Wagner's bionic ear can.  Don't you think we tested that?  We did double blind tests on various victims.  Which sounds better?  That one.  That one.  That one.  That one was the digital one.  When we put the digital converter in the phone, it sounded EVEN BETTER, because the last mile was gone.

That's Anna Log for you.  She was always a mean lady.

But, you had to be less than 3000 feet from the CO.  Beyond that, we had to use Anna without intermediate equipment along the way.  On good copper lines, it didn't make that much of a difference on that extra 7000 feet in terms of sound.

To our dying day, we honored all 1ESS standards that were set in 1965, including the 11 = * so that rotary and 1500 telephones could access vertical service access codes.  SL-100 did Autovon precisely.  People didn't know DMS was behind HALF the lines in America.  We faked everything so well.  Holy mackerel, I've been using an alien phone switch all this time.

We interplayed with SxS by letting them cut through to us on the first dial pull.  Through a simple translation, we "inserted" that first digit on the trunk group SxS used, which was a 5 for locals on the last SxS machine in North America in 2001.  It was in Nantes, QC in 2001, which finally, the operator said, can we have a DMS-10 please to replace this hunk of junk?

Are you sure?  It is the last one in North America.  "Yes, we can't offer any calling features".  Why not keep it up and we'll put the DMS-10 alongside it.  They wanted it gone.  NT pulled the last SxS out of operation that year.  Nobody complained.  I don't know what happened to that switch.

Phreakers didn't understand "the digital" (Mr. Evan Doorbell) when he visited it -- funny watching him get confused as the SxS cut through to DMS and then when digit analysis was engaged, DMS would boot him out when it figured out the number he was dialing was not routable and gave him treatment before he even finished dialing.

I laughed so hard.  Poor guy.  He should have known "the digital".  We understood analog, but they couldn't understand us, and made no attempt to.  Hint:  learn.

We provided the digitone to digipulse CO equipment that allowed those SxS touch-tone subscribers to use their push-button phones on that SxS.  Why do you say SxS is rotary only?

It was very clean sounding, and Mr. Doorbell made note of that.  That was us!  We also provided digipulse pushbutton telephones to SxS or other nXB subscribers beginning in 1976 if the operating company felt that was more cost effective.  It usually was.

We support all and try to play friendly with all switches and analog devices.  That was our style because we were doing it for 100 years.  We would never de-support rotary or any kind of analog communication in or out.  NEVER -- it was against our religion, and there was no need to.  Are you kidding?  Never.  We were EVERGREEN and went to great lengths to ensure that all legacy services would work.

However, our internal switching fabric and inter-DMS communication was digital over optical.  It had to be.  We had the World Line Card to your home, which could do whatever you wanted, minus one or two things where we'd have to change the line card.  Do you want ground start?  Sure!  You have a payphone at home and want polarity reversal?  Sure!  It was the telco who said no.  All they had to do was type in one line in many cases.  Payphone controller from eBay? ... no.  Hello Bell, LCC is COIN, CDF, RCD -- that means coin dialtone first, reverse coin disposal.  Hurry up and type it in.

I'm getting off track again ...

All my crap is 464C compliant for Anna DID or whatever the heck it was killed, I mean called -- wink start, immediate, or delay with pulse, DTMF, or MF inpulsing.

The reason for incoming only is to eliminate any possibility of glare, which analog techniques could only reduce, not eliminate.  PRI solves this by allowing switches to resolve glare and hide it from both parties.

You can also statically map any analog trunk (which is really a line in this case) to any PBX extension using loop start facilities, but that line can be used by nobody else on the PBX.

Outgoing trunks are analog loop start.  We separate them as I said so as to eliminate the possibility of GLARE (when both sides try to seize the line at the same time, causing a collision).

DMS and Meridian through PRI had "YIELD" "STAND" settings to resolve GLARE.  DMS always stood, and Meridian always yielded, so Meridian would back up and make a U turn ... allowing the incoming call to terminate.  If it terminated on the extension that caused the collision which was off hook, it would local hunt step to the next key on that person's phone while he was off hook.  I set it up that way.  Meridian now grabs another PRI to continue his call on the other key.  Now he has to figure out if the incoming guy will hang up before the guy he's calling answers and can say, "hold on a minute".  LOL.

Nobody would ever know a collision occurred.  On analog residential, DMS won every time.  It happened to me a few times.

DMS can also do analog direct inward dial using an IBN line where DMS provides battery.  You set up the analog trunk on the BCM PBX as a DISA.

DMS maps the DIDs to that DN using two tables - DIGMAN and I forget, and rings the PBX -- the PBX answers the call after 2 rings so as to grab the Caller ID -- Dialable Directory Number you know, not the ordinary junk.  Then, DMS will inpulse the digits dialed (all or some as dictated by DIGMAN) and DIGMAN adds the DISA password up front, with pauses, and other command sequences your PBX wants.

During this time, DMS is silent - RINGBACK IS NOT PROVIDED TO THE CALLER even though your PBX has already rung twice and answered and it is sending in touch tones.  It opens up after it finishes the inpulse, and then your PBX's ringback or busy signal or other treatment goes back to the caller.

DMS suppresses audio here so as to provide a transparent experience -- it can't give ringback because it doesn't know if your PBX extension will be busy or what-not, but the effect is it appears your call completion is significantly delayed because PRI is ZAP and so fast.

That's why you use PRI.  But you can't, you gotta SIP trunk now, and Bell can shove that.

BellSystem ... SxS?  You'll be sorry.  Your neighbors will call the cops thinking Chicago mobsters from the 30s are machine gunning you.

Touch-tone?  Digitone.  Your PBX will do the digitone to digipulse conversion you silly goose.  Even Panascenic does that.  That ugly thing most collectors use.  Yuck.

Dominic,
You seem to have some fundamental misunderstandings.

Touch-Tone is an AT&T trademark. It's not a word novices use.
I'm using SxS as shorthand for electromagnetical switches, aka Strowger switches.

SxS switches are fully controlled based off of dial pulses. You can use your switchhook to control them, but you can't use a touch-tone phone to control 'em. TT would have to be converted to DP, and the * and # buttons can't be converted to DP (even though 1167 equates to *67, etc.)

That's like saying you can use a dial phone with a manual Central Office. It's not doable! An operator still has to plug you in.

Panasonic automatically converts DP to TT, although for one of my phones, it's for some reason converting TT to DP... and Panasonic PBX systems are really the only small, lightweight PBXs that have features. I have 2 now. But when I get more phones, I would upgrade to a full-size commercial PBX.

I doubt PRI is disappearing, and I just checked and CenturyLink offers analog trunking (you'll get my business one day!). So does Verizon. And if the phone company doesn't do what I want, screw them: I'll build my own central office and they'll lose my business. Phone service has sucked since 1984.

Even if the telcos. wanted to push SIP, they can't phase out other options. What about places with no or unreliable Internet connectivity? And do you do party-lines with SIP? Rotary phones?
And as soon as people go VoIP, they lose access to dial-0 operator service and don't realize they can't make collect, person-to-person, or station-to-station calls by dialing 0, and then have to dial some 11-digit number just to reach an operator that will rip them off.

So - what would work best for me, do you think? 1ESS? 5ESS? DMS100? DMS500?

BellSystem,

Century Link is DMS.  These are Nortel's DMS SuperNode analog trunk cards.  Buy your SxS and take your pick -- whatever your SxS supports ...

First, read this:

"DMS-100 translations permit the use of the prefix '1' for all billable (non-local) 7 and 10 digit calls. This scheme may be used to provide uniform dialing within an NPA with Step-by-Step (SXS) exchanges (which
require the '1' prefix for routing to a serving CAMA office for billing). If an NPA with this dialing arrangement exhausts the NNX format and uses NPX formats for some office codes, then the code ambiguities can be resolved by the use of a critical (four second) interdigital time-out after the seventh digit."

SxS understands MF (not DTMF), loop, and battery-ground inpulsing for DID (termination)  Outpulsing to DMS is the same.

SxS does not understand DTMF trunk-side.
SxS lineside can be modified with Northern's digitone/digipulse converters.

Century Link will not trunk its DMS to you like this because you are not a telephone company, and SxS is not a PBX.

DMS is digital, but it did route calls to and from SxS machines all the time in its early days when there was a mix of analog and digital.


NT2X72AC Four-wire incoming, outgoing or two-way, DI, DP or MF, E&M trunk circuit.

NT2X78AA Four-wire integrated SF, MF trunk circuit.

NT2X81AB Two-wire incoming, outgoing or two-way, Type DI, DP or MF, E&M trunk circuit.

NT2X82AA Two-wire incoming, loop, reverse battery, DP or MF trunk circuit.

NT2X83AA Two-wire outgoing, loop, reverse battery, DP or MF trunk circuit.

NT2X88AA Four-wire incoming, outgoing or two-way, Type II, DP or MF, E&M.

NT2X92AA Two-wire outgoing, loop, reverse battery, MF trunk circuit.

NT1X54AA Four-wire jack ended trunk circuit.

NT2X65AA Centralized Automatic Message Accounting (CAMA) position signaling circuit.

NT2X66AA CAMA suspension and calls waiting circuit, loop or E&M.

NT2X90AC Incoming or outgoing test trunk, two-wire with S-lead DP, MF, DTMF (DMS-100).

NT2X90AD Incoming or outgoing test trunk, two-wire with S-lead, DP, MF, DTMF (DMS-100).

NT2X95AA Two-way DID/DOD PBX loop trunk. MF, DP (DMS-100).

NT2X98AA Two-way incoming trunk with S-lead control. Reverse battery, DP, MF.

NT3X06AA Outgoing trunk to co-located 3CL switchboard with S-lead supervision. MF, DP, coin, non-coin.

NT3X07AA Incoming trunk from co-located 3CL switchboard MF, non-coin only.

NT5X30AA 101 communication test line circuit.

Quote from: bellsystem on June 29, 2017, 04:15:41 PM
Dominic,
You seem to have some fundamental misunderstandings.

Touch-Tone is an AT&T trademark. It's not a word novices use.
I'm using SxS as shorthand for electromagnetical switches, aka Strowger switches.

SxS switches are fully controlled based off of dial pulses. You can use your switchhook to control them, but you can't use a touch-tone phone to control 'em. TT would have to be converted to DP, and the * and # buttons can't be converted to DP (even though 1167 equates to *67, etc.)

That's like saying you can use a dial phone with a manual Central Office. It's not doable! An operator still has to plug you in.

Panasonic automatically converts DP to TT, although for one of my phones, it's for some reason converting TT to DP... and Panasonic PBX systems are really the only small, lightweight PBXs that have features. I have 2 now. But when I get more phones, I would upgrade to a full-size commercial PBX.

I doubt PRI is disappearing, and I just checked and CenturyLink offers analog trunking (you'll get my business one day!). So does Verizon. And if the phone company doesn't do what I want, screw them: I'll build my own central office and they'll lose my business. Phone service has sucked since 1984.

Even if the telcos. wanted to push SIP, they can't phase out other options. What about places with no or unreliable Internet connectivity? And do you do party-lines with SIP? Rotary phones?
And as soon as people go VoIP, they lose access to dial-0 operator service and don't realize they can't make collect, person-to-person, or station-to-station calls by dialing 0, and then have to dial some 11-digit number just to reach an operator that will rip them off.

So - what would work best for me, do you think? 1ESS? 5ESS? DMS100? DMS500?

What a circus...

I just hope you're making a big joke or just enjoy arousing laughter and ridicule, because your statements and rationale are just unfathomable.  Is it seriously a loss to not need collect calls, person-2-person calls, etc., etc.  when these service were created and useful in times when long-distance costs were exorbitant in comparison today, when it no longer costs any more to make a 2000 mile call than a 2-block call ?  I have not paid long-distance charges anywhere in the US for about ten years or more, and today I make zero-cost international calls to Europe with better quality than ever on any long-distance trunk.  And educate me please, why would I want to talk to a dial-0 operator ? I can't recall doing that in perhaps 30, 40 years, and never did I think of it being a service I desire.   Why would I today want to control a step switch with my switch hook ?

BTW, Touch-Tone was vacated as trademark over 30 years ago.

Finally, you lecture someone about his purported misunderstandings with your level of expertise ?

Unbeldi,
     I don't make $100,000 a year. Long Distance is STILL expensive - $3.95 per month from American Telephone and Telegraph plus $0.15 per minute. A simple 40 minute call easily costs over $6.00.

And how do you deal with answering machines?

Even if nobody's home, if you make a long-distance call and the call is answered by an answering machine, which is pretty typical, you are charged for the call. The only way to avoid this charge is to call the Operator and call person-to-person: this way, you are NOT charged unless someone is actually home.

If you make 1 call per day long-distance, and you dial direct, you waste $0.15 per day. This is a whopping $55 of unnecessary long-distance charges PER YEAR. I don't know about you ubeldi, but I have better things to do with my money than donate it to the phone company.

"When it no longer costs any more to make a 2000 mile call than a 2-block call ?"
Are you serious? If you have a regular phone, there is a HUGE difference in COST. A 2 hour phone call made two blocks away will cost you.... $0.00. A 2,000 mile away phone call, at $0.15 per minute, AT&T's current long-distance rate in Wisconsin, will set you back... $18.

$18 - $0 is NOT equal to $0. Therefore, your statement is not correct. (I realize it's probably true you might have a free long-distance plan or unlimited LD plan. Not everyone does or is willing to pay for that. Just because you don't pay for long distance, doesn't mean everybody else doesn't).

Why would you want to talk to a dial 0 operator? Well first, for station-to-station, collect, and person-to-person calls. And phones with no dial? (I'm sure somebody's got 'em on this forum...) way easier to jab the switchhook ten times for an operator, then ask for her to complete your call, than try switchhook dialing an entire number. Have fun with that,

What if you have trouble dialing a number? Busy Line Verification? Somebody left their phone off-the-hook? Asking for information (esp. for numbers that are not in the telephone directory). These are all situations where the Operator makes your life so much easier than it would be without 'em.

Finally, EMERGENCIES. 2% of the US lacks 911 service. If they didn't have the local police, fire, and medical numbers memorized, and they were NOT able to dial 0, they'd be screwed. And sometimes, 911 is not available - the news is covered with 911 service outages constantly. Recently, someone tried to call 911 from behind a PBX and obviously, got nowhere. Dialing 0, whether you're on a PBX or not, should get you somewhere. If someone is having problems with, or can't call, 911, the Operator is there to help.


I doubt anyone still calls the operator regularly, but they are good person to be able to reach.

Just because YOU don't need to call the Operator and don't see a need for it, doesn't mean that nobody else in the world does. You know that dumpy looking house down the street? Just because you don't live there, doesn't mean you can bulldoze it. Someone else lives there. Other people matter too. If you don't have a use for the Operator, that's understandable. Probably most people don't. That does make her unnecessary. That's like saying "I don't shop at Walmart. Walmart isn't necessary". It doesn't work like that.

And everyone, I am NOT planning on implementing a SxS switch for my primary PBX. Please stop answering my questions in regards to that. I am going to have an electronic PBX.

It's okay unbeldi.  He doesn't understand.  Collectors generally don't.

There was this phreaker who went to Nantes, Quebec, Canada -- the last step by step machine in service, in 2001.

This poor lonely SxS machine (the last) was surrounded by DMS remotes.  This guy (Evan Doorbell?) couldn't even look at the local dialing plan, and because they didn't understand translations, he went kinda nuts, because he couldn't figure out what he considered odd behavior.

That SxS was operating like a PBX.  Calls that terminated within that machine -- 7 digit dialing was not permitted, and he found a payphone (an NT Centurion) and started using it.

The SxS was 819-547-3000 to 3999.  7-digit dialing was in effect and ALL local exchanges around him were served out of various DMS remotes and were 2xx, 4xx, 5xx, 6xx, 7xx, 8xx, 9xx.

3 is missing from nearby local office codes.  That's no accident.  There is no office code starting with 3 in that SxS's local calling area.  There's your answer.

So, a 5 cut thru right away because there were 554, and 58x exchanges nearby that were local.  They did it to save one trunk group.  Obvious to me, but not to him.  He didn't realize that.  So when he dialed 547-xxxx and got treatment before he finished dialing, he couldn't understand it.

The independent obviously asked NT/Bell to disallow loopbacks.  So, it was 4 digit local dialing for the phones connected to that step.

I'd say that town was lucky.  4 digit dialing in 2001!

Easy.  Get an IBN line ... ask for an IBNRTE of "LINE" and DTMF inpulsing.  Buy your DIDs.  Ask for a digit manipulation (DIGMAN) so that you get the last 4.

CenturyLink will map those to your IBN DN.

Get a BCM50 PBX.  Enable DISA on your IBN DN on trunk 061 -- plug that IBN line into trunk 061.

Create a virtual target line for each DID.  Set received digits to the last 4.  Set redirect to the number on your SxS -- put in an access code to grab trunk 062, say 6, for private, and that will tandem the call through from 061 to 062.  Oh, and set the outpulsing mode on 062 to pulse dialing.
 
Done.

And connect 062 from the Nortel BCM to your SxS lineside.  To your SxS, it will look like an analog phone.

Going the other way, HA!  I'll let you figure that out.  If you don't want to use the SxS as a repeater, then ...

fill in the blank.

Or, you could always use Meridian ESN.  That's even more fun.

I make $100,000 a year, and I haven't paid a cent for a LD call in 15 years.  I pay $25 / month for everything. I haven't spoken to an Operator for decades. No need to. Why in Heaven's name are you paying $0.15 per minute?  Because it's making some historically significant or idealistic point to do so?

"It's okay unbeldi.  He doesn't understand.  Collectors generally don't."

He's not a collector, nor is he an operator. He is keeping this conversation going to see how patient and helpful we can be.  Some of his assertions and opinions are incredible. I believe that the term is "troll."

This was moved here in the dead of night with no one else logged in - it just disappeared, but was not removed. It came from this topic in case it needs to be moved back.

     http://www.classicrotaryphones.com/forum/index.php?board=102.0

This move was made after reading this idiotic reply from bellsystem

     http://www.classicrotaryphones.com/forum/index.php?topic=18377.msg189546#msg189546

followed by what appears to be a sarcastic attack on bellsystem by Dominic_ContempraPhones

     http://www.classicrotaryphones.com/forum/index.php?topic=18377.msg189548#msg189548

followed by this apt reply by Victor Lazlo with a possible explanation bellsystem

     http://www.classicrotaryphones.com/forum/index.php?topic=18377.msg189560#msg189560

"He's not a collector, nor is he an operator. He is keeping this conversation going to see how patient and helpful we can be.  Some of his assertions and opinions are incredible. I believe that the term is "troll."

This topic has been spotted in comments in other boards having to do with the friendliness of the CRPF vs ATCA including this post from twocvbloke

     http://www.classicrotaryphones.com/forum/index.php?topic=18378.msg189441#msg189441

when he said "That was quite a long time ago since I used that forum (disagreement with the management siding with a moderator over them claiming my asking for any ideas on what an electronic "thing" I'd acquired was pointless and ridiculous!!), too uptight there, this place here's far more relaxed and they don't mind things sliding off-topic (most of the time!!)..."

followed by a reply to that from new member mickash

     http://www.classicrotaryphones.com/forum/index.php?topic=18378.msg189545#msg189545

saying "It's certainly very relaxed here and without the abuse, bad language and ridicule found on some forums."

Then there is the topic by Doug Rose trying to put the major disagreements in perspective and seemed to not be understood by some of the contentious posters in this moved topic.

     http://www.classicrotaryphones.com/forum/index.php?topic=18393.0

---------------

So, that long distance reply had a lot of stuff between the lines about bellsystem's position which did not need to be replied to, but was, and so I felt it was time to give this topic a break.

This topic can be returned to the original board at any time by anyone by simply removing this reply and deleting the *** xxx *** from the very first topic post before moving it back.


That, in 100 words or more, is my reasoning for moving this out of the public side.

After input from members and discussion of this topic, it was decided that it be re-launched on the public side but locked to further replies - the discussion is closed. Even though this topic was not moving forward to an end (solving the initial topic question) and filled with many replies considered off topic,  it was pointed out that some of the replies contained useful information in themselves.

One of the reasons this has happened was the large number of ad hominem replies and pointed attacks on another member's knowledge, understanding and/or credibility in telephony. Another reason was topic digression, numerous tangents and red herrings taking the discussion far afield from the initial topic question.

With the topic stalled and the discussion becoming contentious, it was decided to end the discussion but to make what was posted available to those who participated and anyone in the future who may find any of the information within useful. It was re-launched in its entirety with nothing deleted, modified, changed or added other than this explanation.

Going forward, this re-launch also make all if the useful information within available to any member who would like to take it upon themselves to extract that information and place it into a document or topic in logical order including an index and glossary for future reference. This summary can be placed where ever appropriate on the forum.

In the future, topics will be watched more closely for digression and contentious replies than in the past. This forum is here to help people, to teach new members, to exchange ideas, to correct errors, to show off phones and to discuss phones or phone systems in a civil and friendly manner.

There is no room for attitude.