PGM 78 Auto Redial wouldn't cause the problem because the redial wouldn't be dialing the problematic C.O. ports. It would dial an external number. Usually when the issue occurs the staff is so tired of hearing the phones ring and dealing with the issue that they give up and reset the system. I thought maybe the residents were using the call back feature so they now when a busy line is free. That only re-calls the extension that chose the feature though. I know weird issue. I'll have to troublshoot some more and keep you posted.

Thanks for the suggestions and time Steve!