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

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

Robert Bonomi (
Tue, 24 May 2005 02:23:47 -0000

In article <>,
<> wrote:

> Robert Bonomi wrote:

>> Autovon used "standard" Touch-tone phones. Ones with *all* the
>> buttons, including the 4th column of 4.

> It wasn't that way at my father's installation, an army arsenal
> and research center.

> [BTW, a "standard" Touch-Tone phones does not have the fourth column.

BTW The Touch-Tone (aka DTMF) _standard_ specifies a grid of four
"low" tones, and four "high" tones.

AUTOVON phones WERE 'standard' in that they used the frequencies that
were in the specification and *only* those things that were in the

They were 'unusual' in that they used *all* the dual-tone pairs
specified in the standard. There was nothing not compliant with the
standard about them.

> Further, plenty of Touch Tone phones introduced in the early years had
> only 10 buttons, not 12. We had such a set at home.]

If you want to get technical about it, the 12 button (and 10 button)
phones are, strictly speaking, "subset implementations" of the full

The fact that subset implementations are more frequently encountered
than the full implementation is irrelevant to the fact that the full
implementation *is* a standard implementation.

> Anyway, my father's installation was all rotary dial served by a cord
> switchboard dial (SxS) PBX accomodating several thousand extensions.

> The Autovon lines came in on trunks that were no different than the
> city trunks and were handled the same way. There were no special
> signals for priority calls or ways for priority handling.

Which proves that that facility was not AUTOVON-enabled, since MLPP
(via the 4th-column touch-tones) was part of the design spec. of
AUTOVON, from "day one".

This was possibly the Army's SCAN. predecessor to AUTOVON.

Or maybe "limited functionality" tie lines to a 'real' AUTOVON

> As mentioned, telephones were plain rotary.

> To reach Autovon they dialed 8 then the Autovon number. For their
> purposes, Autovon was merely a switching tie network to other govt
> installations.

The features and capabilities of AUTOVON, as of its activation in late
1963, are well documented in the literature. Specifically including
'command and control' capabilities using (DTMF-based) MLPP
classification of calls, automatic call pre-emption based on that
'priority', and DID/DOD.

> All incoming calls went through the PBX where the operators connected
> it to the desired extension. Because of the high volume of
> extensions, an extension itself didn't have an appearance, rather a
> dial trunk did. That is, if you wanted extension 7182, the operator
> plugged in the 7 row and dialed 182. I've seen other cord
> switchboards serving very large PBX set up in a similar fashion.

OK, that clarifies things. That base was *not* on AUTOVON, nor it's
predecessor SCAN. They had _limited-functionality_ tie-lines to a
SCAN or AUTOVON facility.

Post Followup Article Use your browser's quoting feature to quote article into reply
Go to Next message: Daryl Gibson: "Re: Tie Lines (was Re: Foreign Exchange (FX) Lines Still in Use?"
Go to Previous message: John C. Fowler: "Re: Foreign Exchange (FX) Lines Still in Use?"
May be in reply to: "Foreign Exchange (FX) Lines Still in Use?"
Next in thread: The Kaminsky Family: "Re: Foreign Exchange (FX) Lines Still in Use?"
TELECOM Digest: Home Page