We have added an billing application, driven by dtmf. it is a vg224 analog switch connected to a dialogic analog gw, that pulls the billing info from the as400, the application is "Inspire-telephony intergration s/w". We are having very, very inconsistent test results and really the vendor has not been able to identify the issue..we on one call will be ok, the next call digits are not recognized, and on the next call double digits are played back. i can plug s/l phone in to 224 dial and answer, and really cannot hear any duplicate digits, i know that probably not the best test but at this time and lack of test equipmaent is all i have.
The vendor seems to think its a cisco related issue, but is unable to show me where the problem resides. if anyone has ran into this please let me know. i have seen posts regarding adding the mgcp dtmf-relay voip codec etc, command which i have added and still the issue happens.
There is a problem with earlier 12.4.15T code involving in band tone leakage at the start of the DTMF detection process on the DSP. This is described in Cisco bug CSCso87127, fixed in DSP firmware bundle 9.4.7 that was integrated in IOS version 12.4.15T8.
It looks like your 3845 is running 12.4.15T5 so you would be exposed.
Try upgrading the code on the gateways to the latest 12.4.15T release.