I have an IPO 406 that we had been using in our office. For a few weeks the phones would have "unknown error" on the display at random times, restarting them and forcing the previous logon off the phone would get it working again. Yesterday the switch stopped completely and the red light on the front comes on solid. There is no response from the serial port, but the built-in hub on the front is still passing data. Any ideas or is my IPO dead?