Author Topic: Spanish Payphone, I need help to make a controller  (Read 11045 times)

Offline G-Man

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Re: Spanish Payphone, I need help to make a controller
« Reply #45 on: December 11, 2013, 03:39:27 AM »
So far I have provided direct quotes from a well respected engineering journal regarding its adaptation in a large number of countries around the world.

I am surprised that you are not familiar with it since Australia implemented it as well. It was used to generate a pulse to indicate when the payphone was to collect the coins.

Aside from regular subscriber message-rate recording functions, pulses generated by this system were used to instruct the payphone as to when to collect the coins/tokens. The message register pulses are delivered via d.c. interruptions, polarity reversals or high-frequency pulses.

Without the pulses delivered from the Karlsson (or any other call accounting) system the payphone would not know when to collect the coins or tokens so yes, it is very relevant to the operation of this payphone. If these pulses were not received by the payphone, it would not be able to collect tokens or coins.

The upshot is that these pulses are very easy to emulate so it will be easy to construct a timing circuit that will collect the tokens, allowing the payphone to be demonstrated to visitors.

*In a recent discussion regarding the use of this system regarding payphones, Steph Kerman incorrectly referred to it as the Karlsen System. Others frequently misspell his name as well.


The Karlsson System for subscriber billing is still in use around the world, albeit the payphones and other equipment are now microprocessor controlled instead of relay based technology.

I still haven't found any documentation for a Karlsson System.

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Searches for newly manufactured payphones reveal that they are commonly available with Karlsson Systems relying on 50KHz, Polarity reversal, 12kHz, and 16kHz pulses.

It must be a broad specification because of the wide variations between each of these.

Any pointers to documentation?

Thanks

Jack
(Only recently interested in payphones)


Offline Jack Ryan

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Re: Spanish Payphone, I need help to make a controller
« Reply #46 on: December 11, 2013, 04:14:11 AM »
So far I have provided direct quotes from a well respected engineering journal regarding its adaptation in a large number of countries around the world.
Well respected but secret – still no reference.

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I am surprised that you are not familiar with it since Australia implemented it as well. It was used to generate a pulse to indicate when the payphone was to collect the coins.
I know what was implemented in Australia but nowhere is it referred to as a Karlsson System.

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Without the pulses delivered from the Karlsson (or any other call accounting) system the payphone would not know when to collect the coins or tokens so yes, it is very relevant to the operation of this payphone. If these pulses were not received by the payphone, it would not be able to collect tokens or coins.
I am well aware of the requirements with respect to tariff and coin/token collection. That is not the issue.

For my education, supply a reference that defines and describes the Karlsson System. Otherwise let’s just drop all reference to a Karlsson System.

Jack

Offline G-Man

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Re: Spanish Payphone, I need help to make a controller
« Reply #47 on: December 11, 2013, 05:17:04 AM »
So far I have provided direct quotes from a well respected engineering journal regarding its adaptation in a large number of countries around the world.
Well respected but secret – still no reference.

Quote
I am surprised that you are not familiar with it since Australia implemented it as well. It was used to generate a pulse to indicate when the payphone was to collect the coins.
I know what was implemented in Australia but nowhere is it referred to as a Karlsson System.

Quote
Without the pulses delivered from the Karlsson (or any other call accounting) system the payphone would not know when to collect the coins or tokens so yes, it is very relevant to the operation of this payphone. If these pulses were not received by the payphone, it would not be able to collect tokens or coins.
I am well aware of the requirements with respect to tariff and coin/token collection. That is not the issue.

For my education, supply a reference that defines and describes the Karlsson System. Otherwise let’s just drop all reference to a Karlsson System.

Jack


You were already given a reference. Contact Steph Kerman or other TCI members if you wish further information regarding it, though there are thousands(?) of hits regarding it on the established search engines.

I am not fixated on the developer’s name and it was given only as an historical context and anyone that is knowledgeable of message-rate billing systems is familiar with it so I thought it would be easier to refer to it as such than to give an overly technical description for it.

Aside from technical details, it is also important to also provide an educational perspective for a full overview. Since I am not aware that you are one of the moderators for this forum, I will not concern myself with your snide remarks. It may suit you better to confine them to your post on the other (3-letter) listseve. I would also suggest that if you feel to post further venomous comments please spare the other members and contact me off-list.

Also, coin/token collection ARE the issue at hand.


Offline Spanish_phones

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Re: Spanish Payphone, I need help to make a controller
« Reply #48 on: December 11, 2013, 05:21:13 AM »
Well, well...

Dsk, I see your point, because I said with polarity reversed, and contact C open, you have dial tone, which means you can talk in the phone. But when I was reading your post, I remembered what happened to me last weekend. I connected the payphone in normal polarity to my Ericsson SIM adapter, to talk on the mobile phone on the payphone. My father called me, and when I answered the phone on the payphone, the polarity changed (because I heard the relay activation inside), and call was ended, and immediately have dial tone but cannot dial neither. When I hung up, polarity reversed to normal. That's why I think the payphone cannot work as you said. These used to receive calls, and you were able to answer without inserting tokens, and that's another problem. How could I make a controller that only works with outgoing calls and not with the incoming ones?


Offline Jack Ryan

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Re: Spanish Payphone, I need help to make a controller
« Reply #49 on: December 11, 2013, 06:36:26 AM »
Re: Karlsson

I suspect that the Karlsson System describes the payphone method in question but outside the USA the method is ubiquitous and has no name. Searches from here receive no hits except the cisco document I mentioned earlier.

The name Karlsson System only exists where it is not used.

Enough said.

Thanks
Jack

Offline G-Man

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Re: Spanish Payphone, I need help to make a controller
« Reply #50 on: December 11, 2013, 07:04:03 AM »
Re: Karlsson

I suspect that the Karlsson System describes the payphone method in question but outside the USA the method is ubiquitous and has no name. Searches from here receive no hits except the cisco document I mentioned earlier.

The name Karlsson System only exists where it is not used.

Enough said.

Thanks
Jack


Actually I have not been able to find technical papers by North American authors, only those by Chapuis, Norwegian and U.K. sources from which I previously quoted from.

So yes, Europe and other countries listed in the quotes by noted International Telecommunications Union Engineer (mentioned above) recognized it specifically as the Karlsson* system.

Since it is a specialized area dealing with message-register toll accounting, I am not surprised that you and others are unfamiliar with it. I am only slightly familiar with it because of my previously research into how other suspension escrow payphones functioned.

But hey, this is what these forums are about, educating ourselves and others about all aspects of telephony.

Thanks.

*As I previously noted Karlsson’s name is often misspelled.






Offline Jack Ryan

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Re: Spanish Payphone, I need help to make a controller
« Reply #51 on: December 11, 2013, 07:25:47 AM »
Actually I have not been able to find technical papers by North American authors, only those by Chapuis, Norwegian and U.K. sources from which I previously quoted from.
That's really all I was after; the references.

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Since it is a specialized area dealing with message-register toll accounting, I am not surprised that you and others are unfamiliar with it.
I am quite familiar with the method - just not the name

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But hey, this is what these forums are about, educating ourselves and others about all aspects of telephony.
Indeed

Anyway, enough of this - it's getting in the way of the payphone analysis. Sorry guys.

Thanks
Jack

Offline dsk

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Re: Spanish Payphone, I need help to make a controller
« Reply #52 on: December 11, 2013, 07:43:54 AM »
I had not heard the name Carlson system on this, but it is commonly used her for payphones. 16 kHz when party answers, and with intervals depending on call rates. 

On the other hand the Spanish payphone here are depending on an abandoned polarity reverse system. This has to be emulated some way.
The line used here are far to sensitive to whats happening, and causes trouble.

The controller has to solve some problems, it must detect incoming calls, and let this signal tell the unit to do nothing. When calling out, it should hold the line while relay changes (a delay) it should detect party answers (ore a suitable timer, and it should collect tokens controlled by another timer.   It may be the the delay could be solved by putting a capacitor of e.g. 5 microfarad across the 100 ohms relay winding, on the other hand this capacitor may cause problems collecting tokens....

dsk
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Offline G-Man

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Re: Spanish Payphone, I need help to make a controller
« Reply #53 on: December 11, 2013, 08:08:25 AM »
I had not heard the name Carlson system on this, but it is commonly used her for payphones. 16 kHz when party answers, and with intervals depending on call rates. 

On the other hand the Spanish payphone here are depending on an abandoned polarity reverse system. This has to be emulated some way.
The line used here are far to sensitive to whats happening, and causes trouble.

The controller has to solve some problems, it must detect incoming calls, and let this signal tell the unit to do nothing. When calling out, it should hold the line while relay changes (a delay) it should detect party answers (ore a suitable timer, and it should collect tokens controlled by another timer.   It may be the the delay could be solved by putting a capacitor of e.g. 5 microfarad across the 100 ohms relay winding, on the other hand this capacitor may cause problems collecting tokens....

dsk


Interesting that you previously haven’t heard of your fellow countryman. As I have previously quoted, S.A. Karlsson was the technical director of the Helsinki Telephone Company. I will once more repeat that the pulses were delivered in various formats including d.c. interruptions or reversals, 50 KHz, 12 KHz, and 16 KHz signals.


Further research shows that this system was used throughout the world and “was developed by S.A. Karlsson, technical director of the Helsinki Telephone Company, who championed the technically simplest solution of keeping the metering pulse sequence out of phase with the theoretical beginning of the call (sending of the called subscriber’s answer signal).

The first pulse in the series was transmitted within a certain margin of exact time determined in respect of the answer criterion.

After much initial hesitation, the Karlsson method swiftly became a great success.”

Some of the countries adopting this system included:
Argentina, Australia, Austria, China, Denmark, Ethiopia, Germany, France, Ireland, Italy, Japan, The Netherlands, Norway, Poland, Portugal, Spain, Sweden, Switzerland, United Kingdom, Yugoslavia.

Countries that DID NOT adopt it include:
The United States, Canada, USSR, Belgium who favored detailed billing information.

Offline Spanish_phones

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Re: Spanish Payphone, I need help to make a controller
« Reply #54 on: December 12, 2013, 07:43:23 PM »
Hi there! I'm afraid I bring you bad news...

I made the simple circuit I showed you and it collects tokens correctly, but affects the call ending it (as I supposed earlier) 

So, I think we have now 2 options:

Try to control the collect coil with "negative pulses/signals", with an extra current and don't reversing the line current.

Try to control the coil shorting the contacts with another current (I don't like this idea very much)

So, now I need how to produce negative pulses and I have no clue of how to make them. :(

Iñaki

Offline Jack Ryan

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Re: Spanish Payphone, I need help to make a controller
« Reply #55 on: December 13, 2013, 12:35:55 AM »
Iñaki,
I am getting a bit lost. The circuit you are using is quite simple but there are many combinations of starting conditions and many possible timing variations that can be applied.

We saw the phone collecting tokens in the video; we know it works. Let’s just take stock of where we are:
1.   At the start of this thread, you explained how the phone worked but that tokens were not collected and were returned when the handset was returned to the hook. You were able to make and receive calls.
2.   You made a video that demonstrated the collection of tokens (even though the last token got stuck – that, I think, is a different issue).

To make the phone collect tokens in the video, I believe you reversed the line polarity and then returned it to normal. That is, the sequence “reversal --> pause --> reversal” caused a token to be collected.

If this is not correct, stop here and report back to the list.

The sequence “reversal --> pause --> reversal” is what I have been calling a “fleeting reversal”. Below, where I say apply a complete fleeting reversal, I mean the complete three step sequence; don’t apply a single reversal or the phone will stop working.

So, to make your phone work:
1.   Lift handset & Insert at least three tokens
2.   Dial the required number.
3.   When the called party answers, apply a complete fleeting reversal to collect the first token.
4.   Continue the call
5.   Apply another complete fleeting reversal to collect the second token
6.   Continue the call
7.   Replace the handset to end the call.
8.   The remaining tokens will be returned.

Did this work as described? If YES, go to Success, otherwise go to Failure.

Failure:
If this sequence does not work, record exactly where it goes wrong and exactly what happened. Report this to the list.

Success:
If this worked then we know (mostly) how the phone works and there are two remaining issues:
1.   How to detect if there is no token when we try to collect one and end the call.
2.   How to create the fleeting reversals automatically.

We’ll worry about that next.

Take your time, good luck.
Jack

Offline dsk

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Re: Spanish Payphone, I need help to make a controller
« Reply #56 on: December 13, 2013, 02:27:37 AM »
I guess I have to focus a little on the line intended to use for this.

Could you please describe the line:

Volts?
max current?
Does it accept rotary?
Do it deliver reverse polarity, and if yes, when?
Does it accept flash or recall pulse? If yes what kind?

dsk
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Offline Spanish_phones

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Re: Spanish Payphone, I need help to make a controller
« Reply #57 on: December 13, 2013, 06:50:41 AM »
I'm sorry for not expressing myself correctly.

Jack Ryan, the fleeting reversal is not the one you described. The polarity stays in normal polarity. To collect a token, you have to reverse polarity only milliseconds, and return it to normal. So the sequence would be:

Normal-->reverse-->normal

Another point is the video that I make. When I showed you how collecting works, a couldn't make a call, dial or anything, because the phone was connected with polarity reversed, and for each token I connected and disconnected the phone from the current, so the coil could do the movements it should do while collecting. But as I explained before, if you have connected the phone with reversed current, you neither have dial tone nor able to dial.

The, in the steps you described, apart from the kind of fleeting it does, it goes wrong in step 4: 3 goes perfectly, collects the first token, but after is collected, I have a busy signal or kind of, maybe is a waiting call signal, because beeping is faster, then if I collect another token, call is reestablished. Really strange. That happens if you reverse polarity just the time to permit the coil to collect the token, if you reverse less time, nothing happens, phone does not collect the token and call continuous.

DSK, here hare the data you required (I measured them with the payphone)

6/6.4 volts (DC obviously)
21.5 mA
Yes, it accepts rotary dialing
No, it doesn't delivers any reversal of polarity
I don't know what flash pulse means. And redial works, but only with the ones they have redial button, and I think redial have nothing to do with the characteristics of the line, only with the phone.

Offline Jack Ryan

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Re: Spanish Payphone, I need help to make a controller
« Reply #58 on: December 13, 2013, 09:27:25 AM »
Iñaki,
OK, there is a minor language problem.

Quote
Jack Ryan, the fleeting reversal is not the one you described. The polarity stays in normal polarity. To collect a token, you have to reverse polarity only milliseconds, and return it to normal. So the sequence would be:
Normal-->reverse-->normal

What you describe as “Normal-->reverse-->normal” is what I mean by a “fleeting reversal”.
The term “reversal” means to reverse the line voltage so “reversal -->pause-->reversal” means:
1.   Change the line voltage from normal to reversed.
2.   Wait for a short time.
3.   Change the line voltage back to normal.
This is a fleeting reversal.

Quote
Another point is the video that I make. When I showed you how collecting works, a couldn't make a call, dial or anything, because the phone was connected with polarity reversed, and for each token I connected and disconnected the phone from the current, so the coil could do the movements it should do while collecting. But as I explained before, if you have connected the phone with reversed current, you neither have dial tone nor able to dial.

As I understand it, when the line voltage is not reversed (that is, when it is normal), you can make a phone call normally. Are you saying that you can’t make a fleeting reversal (that is normal --> reverse --> normal) to collect a coin without losing the connection? The fleeting reversal should only take about a second.

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The, in the steps you described, apart from the kind of fleeting it does, it goes wrong in step 4: 3 goes perfectly, collects the first token, but after is collected, I have a busy signal or kind of, maybe is a waiting call signal, because beeping is faster, then if I collect another token, call is reestablished. Really strange. That happens if you reverse polarity just the time to permit the coil to collect the token, if you reverse less time, nothing happens, phone does not collect the token and call continuous.

OK, it sounds like you have the timing right but the exchange line is doing something I don’t expect. Does your phone line accept a hook flash or similar? If it does, can you turn it off?

I need help from someone here with some European/Spanish telco experience. Dsk (or anyone), what is happening when the coin collection occurs? Assuming the button and relay are being used to generate the reversals, the exchange should see a brief increase in loop impedance to 5k1 ohms plus the loop resistance. Is this being interpreted as a flash of some sort? Without telco experience, logic only takes me so far…

If that is the problem, the actual phone impedance during collection will have to be hidden from the exchange by the controller – no big deal. It looks like this procedure will work.

Jack

Offline poplar1

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Re: Spanish Payphone, I need help to make a controller
« Reply #59 on: December 13, 2013, 10:14:03 AM »
I guess I have to focus a little on the line intended to use for this.

Could you please describe the line:

Volts?
max current?
Does it accept rotary?
Do it deliver reverse polarity, and if yes, when?
Does it accept flash or recall pulse? If yes what kind?

dsk


"Flash" is a timed interrupt button, usually 600* milliseconds, for accessing call waiting, transferring calls, etc.

EDIT: *600 ms in US. Some Cortelco sets are programmable for 300 ms/600 ms. Some sets also have additionally "positive disconnect" that hangs up for long enough to terminate a call.
« Last Edit: December 13, 2013, 02:38:18 PM by poplar1 »
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