I noticed a problem with calls originating from the mod_callcenter. The order of the codecs in the Media Description portion of the SDP is different for calls from mod_callcenter than when dialing the extension from another extension. Specifically, ITU-T G.711 PCMU is coming first on calls that work, and DynamicRTP-Type-98 is coming first on those that don't. A Polycom 450 is returning a 488 Not Acceptable Here message on the callcenter calls, and an Aastra 6731i has extremely choppy audio. If I tell the Aastra to only allow G722, all works as expected. I have my codecs set up in FS as global_codec_prefs=G7221@32000h,G7221@16000h,G722,PCMU,PCMA,GSM Can anyone explain what DynamicRTP-Type-98 is and why it would be in the SDP when I'm not specifying it in the codec list? Here's what the Media Description portion looks like when calling extension to extension: Media Description, name and address (m): audio 10140 RTP/AVP 0 98 99 9 8 3 101 13 Media Type: audio Media Port: 10140 Media Protocol: RTP/AVP Media Format: ITU-T G.711 PCMU Media Format: DynamicRTP-Type-98 Media Format: DynamicRTP-Type-99 Media Format: ITU-T G.722 Media Format: ITU-T G.711 PCMA Media Format: GSM 06.10 Media Format: DynamicRTP-Type-101 Media Format: Comfort noise Here's what the Media Description portion looks like when mod_callcenter initiates the call: Media Description, name and address (m): audio 12606 RTP/AVP 98 99 9 0 8 3 101 13 Media Type: audio Media Port: 12606 Media Protocol: RTP/AVP Media Format: DynamicRTP-Type-98 Media Format: DynamicRTP-Type-99 Media Format: ITU-T G.722 Media Format: ITU-T G.711 PCMU Media Format: ITU-T G.711 PCMA Media Format: GSM 06.10 Media Format: DynamicRTP-Type-101 Media Format: Comfort noise Thanks! -Troy