Some implementations do this in the offer in the reINVITE. It would include the 
T38 image and G711 PCMU/PCMA just in case the other side doesn't do T38. The 
answerer side should choose T38 and mute G711 codecs, if it can handle T38. 
Otherwise, if it can't handle T38 but can handle a G711 codec type, it should 
mute T38 and accept PCMU or PCMA.
This implementation is consistent with the offer/answer model RFC3264 with 
examples in RFC4317.

-----Original Message-----
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of EDLER, Franz
Sent: Monday, February 20, 2006 9:08 AM
To: [email protected]
Subject: [Sip-implementors] ´Problem with a T.38 call

Hello T.38 experts,

I am faced with an issue, that a SIP Terminal-Adapter after detecting a T.38 
preamble sends a Re-INVITE with two media streams in SDP (audio and image), but 
without muting the audio. The other side (a SIP/PSTN gateway) does not honor 
the image media in SDP and continues the audio media anly. The vendor of the 
gateway claims that there MUST be only one media stream (not both audio amd 
image).

The question is: Who is right and who is wrong?
Are there any clear arguments?

regards
Franz



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