Hi Brian, Thanks for the quick answer. I am not sure if you mean the codec section in the external or internal xml. I was able to make it work in media bypass but I would like to be able to do IVR treatment. I added this to the vars.xml   <X-PRE-PROCESS cmd="set" data="global_codec_prefs=G722,PCMU,PCMA,GSM,OPUS,VP8"/>   <X-PRE-PROCESS cmd="set" data="outbound_codec_prefs=PCMU,PCMA,GSM,OPUS,VP8"/> And when I check the registration, I see  OUTBOUND-PROXY          N/A CODECS IN               G722,PCMU,PCMA,GSM,OPUS,VP8 CODECS OUT              G722,PCMU,PCMA,GSM,OPUS,VP8 TEL-EVENT               101 DTMF-MODE               rfc2833 But still no dice. Sorry for the stupid questions... Thx holger