Hi Jeff,
We think we've finally got what you're meaning. In the Media Announcement attribute "m=audio 49152 RTP/AVP 0 8", the last figures list simply means codes specifying codecs, i.e. 0-g711 pcmu, 8-g711 pcma.
We'll see if it works. Unfortunately, GSM vendors' implementations sometimes don't work even if everything is conforming the RFC.
P.S. The link that you've shared pointing to RFC seems broken because it navigates to the completely non-IT related web-page.
