CallManager 3.3(3) & 6624 disconnect problems

[chriss]

I have a 6624 FXS blade in a 6500 switch running CAT OS with CallManager 3.3(3). The 6624 ports are being used to trunk to a Siemens PBX to provide PSTN access through several PRIs that are terminating into a 6608 blade on the 6500. I am having an issue where periodically the FXS ports do not hang up after a call is completed from the Siemens PBX. Is there some place where I can adjust some kind of threshold either in CallManager or on the 6500 so that it will register that the Siemens PBX has disconnected?

[dgahm]

Are you using loop start? If so you might consider changing to ground start. Loop start has serious disconnect supervision issues that may be causing your problems.