costomer has a summit ksu. ext 103 always beeps over the speaker when on hook. they take it off hook and it is ok. they can use the phone. they tried a differant phone and it did the same thing. they did tell me the mailbox is full. could that be a warning the mailbox is full. i have never had this happen before. its a rather long drive so i want to get all the info i can before i go out there. thanks. dave