[SIPForum-discussion] Prefered audio codec

Jeff Wright JWright at azteknetworks.net
Wed Dec 12 16:19:35 UTC 2007

My experience in the past has shown that G.729a will do a better job
than most LBRCs (low bit rate codecs) of passing DTMF digits (and tones
in general).  It certainly is a lot better than G.723.1.  But don't bet
the bank on it.  Make sure you have "wide" digits (i.e. at least 100ms
duration both on and off) from the phone device.


Is there any reason you have to pass the digits through the voice path?
Why not use some digit relay protocol like RFC4733?


Jeffrey D. Wright

System Test Engineering Manager

Aztek Networks, Inc.

(303) 415 6149

jwright at azteknetworks.net




From: discussion-bounces at sipforum.org
[mailto:discussion-bounces at sipforum.org] On Behalf Of Fredrik Sandedal
Sent: Tuesday, December 11, 2007 12:50 AM
To: discussion at sipforum.org
Subject: [SIPForum-discussion] Prefered audio codec




Could someone give me suggestions on the best audio codec to use when
DTMF is necessary and the bandwidth must be kept on a low rate?


I heard that there could be problems with DTMF and G729AnnexA but I
haven't been able to do any advanced test with this.




Fredrik Sandedal, Enera


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