RightFax sending fax across SIP Trunk to CallManager 8.5.1 that has Device > Trunk (SIP) to 2811 (Branch Router with PRI) that have Early Offer.
Faxes fail outbound. Seeing CallManager Software MTP being invoked in ccm trace files;
“RigthFax doesn't support any type of DTMF, whereas the SIP Trunk supports
RFC2833, the CUCM understands this as a mismatch and allocates the MTP:
MTP_DHSCCMSUB4. Below the initial INVITE coming from Rightfax where you can
see inside the SDP there is no DTMF attribute”
Anyone aware of this and if RightFax has a fix for RightFax to include DTMF attributes in their SIP SDPs so MTP doesn’t get invoked?
