With MGCP, the modem Passthrough should be enabled in order to have Super G3 fax sent

what type of FXO card are you using? general FXO or FXO-M1/FXO-M2?

When the ccm comes back, the phone will automatically goes back to CCM

the ISDN cause 60 was SERVICE NOT ALLOWED. Could you also capture "debug isdn q931" and "debug isdn event"?

Pls check the links for VoIP over slow linkshttp://www.cisco.com/warp/customer/788/voice-qos/voip-ov-fr-qos.htmlhttp://www.cisco.com/warp/customer/788/voice-qos/voip-mlppp.html