During a recent upgrade from PBXinaFlash running Asterisk version 1.4.21.x, to PBXinaFlash version 1.7.554 bronze (Asterisk version 1.6.15), we encountered a problem with inbound DTMF from Cbeyond SIPconnect. The solution to the problem is detailed below.
The SIPconnect trunk settings were identical to the 1.4 version, however the DTMF tones were not coming through from the SIP trunk. After a lot of debugging and many iterations of DTMF settings on the trunk (including dtmfmode=auto, dtmfmode=inband, relaxdtmf=yes, relaxdtmf=no, and insecure setting variations) with no luck, someone at Cbeyond suggested that we remove the DTMF settings from the trunk and set them globally. This was accomplished by removing dtmfmode=auto and relaxdtmf=yes from the trunk settings. We then used the Asterisk SIP Settings module (from the extended repository) to add dtmfmode=inband and relaxdtmf=yes in the ‘Other SIP Settings’ section of the module. We applied the changes and everything worked perfectly!
