Okay, I have run across a situation that I have troubleshot with TAC extensively.  As one final shot at resolving this I am bringing the question to all of you.  The problem in a nutshell is DTMF is not passed to an "IVR" type of service that requests authentication codes for customer's LD use.  This service runs on the network at the carrier.  This works from everywhere except the Turret trader phones and even works from them to other IVRs, just not this service.  The essential call flow is as follows: Unigy Turret phone system -----SIP Trnk--->CUCM 8.6------SIP Trnk------>3945------tie line------>Nortel switch-------PRI----->AT&T MTP (software) enabled on SIP trunk facing 3945 3945 IOS ver = 3900-universalk9-mz.SPA.151-4.M4.bin Okay, hit me with all of the questions and requests for more info and I'll do my best to provide.  I have seen similiar issues resolved the moment the MTP was checked.  That is not the experience this time.  I'm sure it has to do with early-offer and responses from the carrier on this particular service not reaching back across the system to the Turret and negotiating appropriate DTMF correctly or sending the correct notices.  Would a hardware MTP work better perhaps?  Would a different ver of IOS perhaps a "T" code work better?  If you've seen this type of thing before please hit me up and let me know what the resolution was. Thanks in advance for your assistance!! Regards, Jarrod ... View more