10-20-2008 12:07 AM - edited 03-15-2019 02:02 PM
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
sip
!
dial-peer voice 50 voip
destination-pattern [45]...
voice-class codec 1
session protocol sipv2
session target ipv4:10.116.0.12
dtmf-relay sip-kpml
fax rate disable
no vad
!
Thanks a lot for your comments.
Regards
Julien.
10-24-2008 06:41 AM
Software MTP does not support T.38 fax or fax pass-through. With 5.1 CM, you need hardware MTP for your scenario.
10-24-2008 06:58 AM
Hello, thanks a lot for your answer.
I have to try this settings:
"MTP is required" on the Trunk to be able to listen to pstn messages.
+
Hardware MTP for fax passthrough support.
Do you mean that with CUCM 6.X, software MTP support passthrough and T.38 ?
Thanks again.
Julien.
11-12-2008 09:18 AM
Hello, i configured hardware MTP on 2801 gateway + hardware transcoder (if needed).
=> Fax transmissions failed, passthrough was not operating correctly.
I did not understand why dsp ressources on 2801 were not allocated when a call was placed through the SIP Trunk with MTP required checked (no need ???, show sccp connections did not show any allocation).
I have placed the hardware ressources at the top of Media Ressource Gpe List and removed software MTP from this MRGLST and reset the trunk.
Any help would be precious !
Julien.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide