There are a lot of litterature / Documentation concerning Fax in a Cisco VoIP Environment.
Problem is we can easely get lost regarding all the possible configuration, ie Fax Relay, T38 Fax Relay, Modem Passthrough, Fax Passthrough, combination with H323, MGCP or SIP and finally I could not get a simple example that would make my Fax work :)
Running CUCME 6.1, GW 3825, HWIC-8-FXS-DID card, E1, MGCP. The GW works fine and the FXS analog port also, when using a analog phone. However fax transmission causes some problems. Failure after communication is established. I aim at using Modem passthrough.
current mgcp config:
mgcp call-agent 10.126.0.225 2427 service-type mgcp version 0.1
mgcp dtmf-relay voip codec all mode out-of-band
mgcp rtp unreachable timeout 1000 action notify
mgcp modem passthrough voip mode nse
mgcp package-capability rtp-package
mgcp package-capability sst-package
mgcp package-capability pre-package
no mgcp package-capability res-package
no mgcp package-capability fxr-package
no mgcp timer receive-rtcp
mgcp sdp simple
mgcp rtp payload-type g726r16 static
mgcp bind control source-interface Loopback0
mgcp bind media source-interface Loopback0
Thanks for your help.