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From: dave@westmark.westmark.com (Dave Levenson)
Newsgroups: comp.dcom.telecom
Subject: Re: The Tone That Prompts For Calling Card Number
Message-ID: <15209@accuvax.nwu.edu>
Date: 5 Dec 90 03:27:24 GMT
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X-Telecom-Digest: Volume 10, Issue 864, Message 12 of 14


In article <15178@accuvax.nwu.edu>, jon_sree@world.std.com (Jon
Sreekanth) writes:

> What are the specs on that tone? Frequency (single, or mixture of
> frequencies), envelope, duration, etc.

 From "Notes on the BOC Intra-LATA Networks" Bellcore, 1983:

Calling Card Service-Prompt Tone:

941 Hz + 1477 Hz for 60 milliseconds, at -10 dBm0/frequency at -3 TLP
(-7 dBm0) followed by 440 Hz + 350 Hz for 940 milliseconds
(exponentially decayed from -10 dBm per frequency at -3 TLP at time
constant of 200 milliseconds).

Note that the initial 60 milliseconds of 941 + 1477 is the equivalent
of the touch tone # symbol.  This is done because the # will disable
the tone-to-pulse translators used on some older central office and
PBX equipment.  A caller using a tone-dial phone behind a tone-to-
pulse converter will thereby be allowed to send the calling-card
number using tones.

The rest of the tone (after the # symbol) is a decaying dial-tone.


Dave Levenson			Internet: dave@westmark.com
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