Could be the following:CSCsc76080 Bug DetailsMGCP gateway fails to bring up backhaul, when BRI is in power save mode Symptom:Gateway fails to bring up L1/L2 for BRI MGCP backhaulConditions:Callmanager 4.1(3) IOS Gateway configured for BRI Backhaul...
Depends on what you have configured on your voip dial peer that is used to send to your SIP provider.Most SIP providers support RFC2833 for dtmf relay, on the voip dial peer it would be configured as dtmf-relay rtp-nte.The debug to see this would be ...
Show tech when all is ok most likely will most likely not provide much useful info.You can alway run it through "Output Interpreter" on cisco.com to help:https://www.cisco.com/cgi-bin/Support/OutputInterpreter/home.pl