TELECOM Digest OnLine - Sorted: Re: Foreign Exchange (FX) Lines Still in Use?

Re: Foreign Exchange (FX) Lines Still in Use?

The Kaminsky Family (
Wed, 25 May 2005 09:39:13 GMT

Al Gillis wrote:

> Robert Bonomi <> wrote in message

>> In article <>, TELECOM Digest
>> Editor noted in response to Robert Bonomi:

>>> [TELECOM Digest Editor's Note: As Robert knows, those four additional
>>> touch tone keys were known as A,B,C, and D. I forget the exact
>>> meaning of each, but my question is, did anyone with 'regular'
>>> service but with an Autovon phone ever try pressing those keys in
>>> a regular call? I did a couple times, and the immediate result was
>>> a 'fast busy' signal; the call would not complete. PAT]

>> On the PSTN, it somewhat depended on the switch and programming.
>> 'Reorder' was the very-common switch reaction. There were a few
>> switches that completely 'ignored' those signals.

>> [TELECOM Digest Editor's Note: But did you ever see/hear any that
>> neither ignored nor offered re-order, but instead actually _did
>> something_ ? I never did. PAT]

> I've got a Western Electric 3666-1A key set (Autovon dial). I've
> tried pressing the A, B, C and D keys while connected to both a
> Nortel DMS-200 (CO Switch) and a Nortel Meridian-1 (PBX). In both
> cases I got reorder while listening to dial tone (that is, no call
> had been established yet) and no effect while an established call
> was in progress.

> The Names of the additional keys are:
> FO (Flash Override) adjacent to the 3 key
> F (Flash) adjacent to the 6 key
> I (Immeadiate) adjacent to the 9 key
> P (Priority) adjacent to the # key (See note)

> Note: My 3666-1A has a key designated as "A" where the # key is placed
> on a normal dial pad. I don't know if this is standard for "Autovon"
> dials. The tone generated by this key (according to a "digit
> grabber") is that of a # key, however. Another interesting thing is
> that the Star key (left of 0) is not an asterisk but rather it's a
> real star! That is, a five pointed star, white lines on the gray
> background (or is it a grey background?) with a hollow center.

> Al

It has been at least ten years since I worked on this stuff, so if any
of it matters to you, please do not rely on my memories.

When I was working for a voice messaging vendor, we were part of an
industry initiative to develop a protocol for passing messages between
messaging systems from different vendors. The relevant specification
was for the AMIS Analog protocol (and I've forgotten what the acronym
AMIS stands for).

Basically, the protocol allowed a user of one voice messaging system
to address a message to a user of another voice messaging system (the
user interface was left unspecified -- that was a matter for the
individual vendors to handle), in such a way that the voice messaging
system could then dial the recipient system, do some handshaking, and
then deliver the message in a way that allowed the recipient system to
deliver the message to the intended voice mailbox.

The protocol relied on use of two fourth-column tones (C and D, as I
recall) to screen out nearly all accidental calls to the incoming AMIS
Analog phone number (I forget if the specification required it, but we
came up with a canned message to play if that phone number received an
incoming call that did not send the correct tone -- just to be polite).

It was quite a change from our usual workday (writing documents or
code, and testing code) when we got to test with other vendors. We
actually got to talk to engineers working for our competitors, and
send each other messages (mostly we sent protocol errors, actually, to
verify that the error handling on both sides was working properly - it
does not take very many correct messages to verify that things work
properly). I still remember one of our competitors (who really should
have known better) who had the wrong country code for the US - but
otherwise, there were not many problems getting things to work.

Security was an issue -- once the testing period was over, our
management refused to allow an incoming telephone number - so other
members of the AMIS committee could not send us AMIS Analog messages
(rather frustrating, but out of my control).

I had a four column analog phone on my desk for a few years while I
worked on this system (the fourth column, if I remember correctly, was
to the right of the normal three columns, with the rows 1-2-3-A,
4-5-6-B, 7-8-9-C, and *-0-#-D). When I was doing it often, I was able
to manually imitate a voice messaging system, computing checksums as
needed in my head (there were not very many of them, and only two were
variable, if memory serves). The protocol had to be designed to
handle some slow systems, so I could dial fairly slowly when I was
adding the checksums.


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