Subject: DTMF & SIP

From: "Jacob Avraham" <[email-masked]>
Date: Wed, 7 Jul 1999 16:30:49 +0300

Is there any mechanism in SIP to transfer DTMF (not in the RTP stream)
during the call? Or, if this is outside the scope of SIP, what companion
protocol is used to do that?

Thanks,

Jacob Avraham
Mediagate

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From: Jonathan Rosenberg <[email-masked]>
Date: Wed, 07 Jul 1999 23:00:22 -0400

This is one of the proposed uses of the INFO method, documented in:

http://www.ietf.org/internet-drafts/draft-ietf-mmusic-sip-info-method-00.txt

Whether or not its actually a good idea to carry DTMF out of band is a
good question... 

-Jonathan R.

Jacob Avraham wrote:
> ---------
> This message came from the IETF IPTEL Working Group Mailing List.

-- 
Jonathan D. Rosenberg                       Lucent Technologies
Member of Technical Staff                   101 Crawfords Corner Rd.
High Speed Networks Research                Holmdel, NJ 07733
FAX: (732) 834-5379                         Rm. 4C-526
EMAIL: [email-masked]
URL: http://www.cs.columbia.edu/~jdrosen

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From: Scott Petrack <[email-masked]>
Date: Thu, 8 Jul 1999 07:25:45 -0400 (EDT)

There seem to be at least two different ways to encode DTMF information
now -- by an MGCP notification, or by an RTP payload. I personally would
have no problem encoding the RTP payload within MIME (of type 
audio/rtp ?) to be put within a SIP payload, but what would the purpose
really be? 

If you take the real-time info out of the DTMF, then you are left with a
string of digits. What is the purpose of transporting such a string of
digits within SIP?

Scott