Hi, Whenever my provider puts me on hold, it reINVITES with an SDP containing both audio (sendonly) and image media like so: ... m=audio 5320 RTP/AVP 18 3 8 0 96 c=IN IP4 <ip_address> a=rtpmap:18 G729/8000 a=rtpmap:3 GSM/8000 a=rtpmap:8 PCMA/8000 a=rtpmap:0 PCMU/8000 a=sendonly a=rtpmap:96 telephone-event/8000 m=image 5322 udptl t38 c=IN IP4 <ip_address> a=T38FaxVersion:0 a=T38MaxBitRate:14400 a=T38FaxUdpEC:t38UDPRedundancy a=T38FaxRateManagement:transferredTCF Not sure if it's a non-standard SDP, but that's what I get. Now when t38_passthru=true, it only forwards the "image" part to the other leg. When t38_passthru=false, it only forwards the "audio" part. Is there a way to make t38_passthru forward the audio part as well? Or should I just change to a better provider? Thanks, François.