Path: utzoo!attcan!uunet!cs.utexas.edu!sun-barr!texsun!texbell!vector!telecom-gateway
From: stiatl!tom@gatech.edu (Tom Wiencko)
Newsgroups: comp.dcom.telecom
Subject: Re: The Tone Which Announces Request for Card Number
Message-ID: <telecom-v09i0268m04@vector.dallas.tx.us>
Date: 1 Aug 89 18:45:31 GMT
Sender: news@vector.Dallas.TX.US
Reply-To: Tom Wiencko <stiatl!tom@gatech.edu>
Organization: Sales Technologies Inc., "The Procedure IS the product"
Lines: 21
Approved: telecom-request@vector.dallas.tx.us
X-Submissions-To: telecom@eecs.nwu.edu
X-Administrivia-To: telecom-request@vector.dallas.tx.us
X-TELECOM-Digest: volume 9, issue 268, message 4 of 11

In article <telecom-v09i0265m05@vector.dallas.tx.us> 89.KREMEN@gsb-how.stanford
 .edu (The Arb) writes:
>I am wondering about the "special tone" that one hears when
>making a telephone credit card call using AT&T. Does anyone out know
>at what frequency the tone is or is there even a standard?

As a matter of fact, yes, there is a standard.  My copy of the 1980
"Notes on the Network" tells it like this:

A 941Hz plus 1477Hz tone for 60 msec at -10dBm/-3TLP

followed by

a 440Hz plus 350Hz tone for 940 msec exponentially decayed from
   -10dBm per frequency at -3TLP at time constant of 200 msec.

This tone is affectionately known in some circles as the "bong."

I believe that this is still the standard.

Tom