Author Topic: How is a phone line "conditioned" to disallow rotary dialing  (Read 411 times)

Offline RotoTech99

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How is a phone line "conditioned" to disallow rotary dialing
« on: November 16, 2020, 09:55:38 AM »
Dear Forum:

I have a question please about how telephone companies "condition" their central office or a subscriber's line to only accept one type of dialing?

I know that it used to be, and maybe still is in a few areas, rotary dialing only is used due to the equipment at the central office, and in others, they can accept tone dialing, but it is enabled by setting up the subscriber's line to do so.

And in some central office areas, both rotary and tone dialing can be used without the tone service having to be enabled... My main question is how rotary dialing is disallowed by a company that chooses to use only tone dialing, and why; it seems counter-productive in a way.

Can the Forum members please explain this so i can better understand it, I would be appreciative and Thankful
for whatever you can tell me.

Thanks, RotoTech99

Offline Owain

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #1 on: November 16, 2020, 01:07:20 PM »
These days it will all be done in software in the exchange.
There is no reason why a subscriber's line interface card (SLIC) can't understand loop disconnect dialling, as it has to sense line current for on-hook and off-hook.
In some cases the telco might still restrict access to tone dialling if there are limited tone decoders, but I think that would really only be in electromechanical exchanges now.

Offline RotoTech99

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #2 on: November 16, 2020, 01:54:05 PM »
Dear Owain:

What I was thinking about when I posted my topic was how/why some telco's condition a line to accept only tone dialing, and not allow rotary dialing...... That's what I didn't understand.

RotoTech99

Offline Owain

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #3 on: November 16, 2020, 04:45:08 PM »
How is done in software.
Why, I can only guess at (a) some strange local tariff regulation (b) a line has a history of intermittent shorts/disconnections causing false dialling by loop disconnect, but tone dialling is immune to false dialling.

Offline RB

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #4 on: November 16, 2020, 05:47:50 PM »
The short answer...cost.
It took a bunch of power to keep the old step units running.
Digital, not too much at all...compared.
When new ideas come out, there is an effort to de commission the old.
No one wants to offer a new product, and tell customers they can keep
doing what they were. or no one would buy the new.
Also, I would imagine, the new systems were not as robust.
That means, digital stuff does not enjoy connect to power, dis connect. Connect, dis connect.
That stuff tends to blow up ic's.
And, someone made a pulse to tone converter...
No one made a tone to pulse converter...
All this is my opinion, so don't believe a word of it!
Beer

Online countryman

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #5 on: November 17, 2020, 02:09:57 AM »
My guess is, that in many cases the classic exchanges are long gone and replaced with VOIP interfaces for customers who want plain old telephone service. These may or may not understand pulse dialing.

Offline Doug Rose

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #6 on: November 17, 2020, 08:30:14 AM »
In the early 2000s we installed a Alcatel PCX in our location replacing a NEC. It has since been replaced by an Avaya as we connected all our Global offices.

I always kept a 302 on my desk connected as an extension, definitely a conversation starter. I also picked up a few phones from this office advertising.  8)  I would dial it to show people what a ring used to be like as it did not break dial tone with the NEC.

I was showing someone the ring, they picked it up, hung up and called my extension and it worked!

It amazed me, the Alcatel did support rotary dial. Alas, the Avaya does not....Doug
Kidphone

Offline SUnset2

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #7 on: November 17, 2020, 11:38:02 PM »
If you're still connected with copper to the central office, rotary is pretty likely to be supported.  If you are on fiber optic cable with an adapter, your luck will vary.  We moved to fiber optic a couple years ago to get faster internet, and the adapter from Century Link works fine with rotary dialing, and Touch-Tone too. 

I had a different situation when I was first living on my own in the early 1980s.  I signed up for rotary service, because I was too cheap to pay the extra monthly fee for Touch-Tone service.  Somewhere I had picked up a Touch-Tone phone, and I plugged it in just for laughs.  Sure enough, it worked.  I ended up using it for my primary desk phone.  It turns out that the No. 1 Crossbar I was on did not have the capability to identify class-of-service for Touch-Tone, so everybody got it, even if they weren't paying extra for it.  Another odd thing was that I was on on two-ring cadence, even though I had a private line.  Anyway, about 1984, they replaced the 1XB with a No. 5 ESS digital.  Lo and behold, my Touch-Tone phone didn't work anymore.  And I now had a standard US ringing cadence.  So the 2500 had to go back in the box, and be replaced by a 500.  I wasn't going to pay extra for Touch-Tone when it actually cost the phone company more to provide rotary service.  I brought out a Touch-Tone phone again a few years later when they stopped charging extra for it.

Offline tubaman

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #8 on: November 18, 2020, 02:45:38 AM »
...  I signed up for rotary service, because I was too cheap to pay the extra monthly fee for Touch-Tone service.  ...

Wow, even British Telecom didn't think of that one when they introduced new exchange technology, and they usually charge for every little thing even if it costs them nothing (eg Caller Display used to be a chargeable extra).
 :)

Offline Jim Stettler

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Re: How is a phone line "conditioned" to disallow rotary dialing
« Reply #9 on: November 24, 2020, 05:38:53 PM »
Dear Owain:

What I was thinking about when I posted my topic was how/why some telco's condition a line to accept only tone dialing, and not allow rotary dialing...... That's what I didn't understand.

RotoTech99

The original reason was that pulse takes more switching time, which cuts down on the switching capability.


Only tone would be on a VOIP type line.
Prior to that, the equipment had to be able to switch old technology.
With digital type lines they can block pulse as well as tap the line without a court order.
The technology changed as well as the rules.
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In the 1980's I paid extra for DTMF.
In 1995 my boss was told he needed to start using a TT phone as his main phone, or pay an extra fee.
I gave him a TT trimline. His wife liked it so well I gave him 2 more.
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Pulse dialing takes longer, If people use tone, you have a more effective use of service.

I can get an instant rebate on low energy light bulbs for the same reason. If people drop the demand on service, current facilities have higher effective ability.
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To get back to the main point, It is only a software issue for  a VOIP type line .
It doesn't tie up switchgear to process pulse, everything is data.
JMO,
JIm
>>edit<< with hybrid pbx's, x-link, dial gizmo's ect, this problem goes away>>edit<<
You live, You learn,
You die, you forget it all.