Batboard

picked up a couple of surplus 4550's. Same cable Same computer one radio read and writes fine. The other never even activates as an active USB device insertion. The service manual for a 4{3,5}80 shows the rear accessory connector USB2 ESD protection diode D4000.



My 4550 board is probably totally different but my guess it the interface circuity is similar. Suggestions?

What is the firmware version? R01.08.20 had some issues with connectivity. May not be a hardware problem.

older then dirt - 1.02 i think

Have you tried both the rear accessory cable & the front mic cable?

rear yes - front no - looking into it now..