Hi, I have very limited info but I'm looking to point someone in the right direction. My colleague has the following setup in Europe. Cisco Call Manager version 7.1 with ISDN trunks to the PSTN. The Call Manager has SIP trunks to an Aspect Call Center. The problem is, when someone from outside calls a number on the call manager that is routed over to the Aspect system, the caller is not able to dial DTMF that can be heard/understood by the Aspect system. However, if a user of a Call Manager phone picks up a phone and dials the same number internally, DTMF does work over the SIP trunks to this Aspect system. It would seem there's some sort of issue with DTMF passing through the ISDN trunks, through the CCM and ultimately over to the Aspect system. Do you have a recommendation on where to start looking to resolve this problem?