Hello guys, i would like to know if fax passthrough is supported with a SIP Trunk with "MTP is required" checked ?
I had to check the "MTP is required", because of conferences with outside users that did not work and because of PSTN prompt not played correctly to ip phones. As soon as i checked the box, fax transmissions failed.
CUCM 5.1(3) + 2801 gateway
GW configuration for fax passthrough:
voice service voip
modem passthrough nse codec g711alaw
dial-peer voice 50 voip
voice-class codec 1
session protocol sipv2
session target ipv4:10.116.0.12
fax rate disable
Thanks a lot for your comments.