Subject: [AVT] Henning: Another rfc2833 correction

From: Rajesh Kumar <[email-masked]>
Date: Wed, 18 Jul 2001 17:54:08 -0700

Henning,
rfc2833 defines the following:

	 Continuity test send: A tone of 1780 Hz is sent by the calling
            exchange. If received by the called exchange, it returns a
            "continuity verified" tone.

      	 Continuity verified: A tone of 2010 Hz. This is a response tone,
            used in dual-tone procedures.

This is defined per obsolete specifications. Formerly, 1780 Hz was the go 
tone and 2010 Hz was the response tone in dual tone COT procedures.

This has changed!!  If you look at current versions of  ITU-T Q.724 or 
the  Bellcore GR-317-CORE specifications, you will see that *either tone* 
can serve as the go tone, and either tone can serve as the return tone. 
Therefore, you should change the definitions as follows:

  	Continuity test send: A tone of 1780 or 2010 Hz is sent by the calling
            exchange. If received by the called exchange, it returns a
            "continuity verified" tone.

       	Continuity verified: A tone of 1780 Hz or 2010 Hz. This is a 
response tone,
            used in dual-tone procedures. If the sent tone was 1780 Hz, 
then a 2010 Hz
             tone is returned, and vice versa.

Thanks!
  Rajesh Kumar
--------------------------------------------------------
Cisco Voice Technology Center
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Audio/Video Transport Working Group
[email-masked]
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From: "Henning G. Schulzrinne" <[email-masked]>
Date: Thu, 19 Jul 2001 14:50:07 -0400

Thanks for the correction; noted in my working draft. Part of the
problem is that I don't have easy access to the Bellcore specs (and
don't have $1000 to pay for them...). I'm in the process of collecting
these changes and will put out a new revision
(draft-ietf-avt-rfc2833bis-00) before London.

-- 
Henning Schulzrinne   http://www.cs.columbia.edu/~hgs