I have just recently installed an IPO 500 V2 running 8.1 (69) and VM Pro. In the control unit there is a Phone 8 in the first slot, a VCM/PRI in the second slot and a UC Module in the third slot. There is also a DS16 and a DS30 connected to the system. The CO has been doing some maintenance on their fiber and every time they take the PRI down in the middle of the night, the phone system does not recover when they bring it back up. Last week I went over there and pulled the PRI out of the system, waited about 30 seconds, then put it back in, waited a couple minutes but not recovery. The system requires a reboot in order to start operating properly again. Before the reboot an incoming call will get a busy signal and trying to place an outbound call results is "Waiting for Line". I had Monitor running when I intentionally took it down and brought it back. I have sent that to my distributors tech's and they find nothing out of the ordinary. Any ideas on where to turn next?