The following tyntec descriptions comply with RFC 3555 and RFC 4566.
Example for Voice Inbound:
Content-Type: application/sdp v=0 o=- 1321474370742 1321474370742 IN IP4 1.2.3.4 s=- c=IN IP4 1.2.3.4 t=0 0 m=audio 41730 RTP/AVP 0 8 18 a=nortpproxy:yes
Example for Voice Outbound:
Content-Type: application/sdp v=0 o=- 1321474370742 1321474370742 IN IP4 1.2.3.4 s=- c=IN IP4 1.2.3.4 t=0 0 m=audio 41730 RTP/AVP 0 8 18 101 a=rtpmap:0 PCMU/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:18 G729/8000 a=fmtp:18 annexb=no a=rtpmap:101 telephone-event/8000 a=fmtp:101 0-16 a=ptime:20