|bottom of the unit Pin||Pin
|1||ext. power||3.3v externally regulated. DO NOT FEED WITH 12 VOLTS!|
|2||serial in||RS232 data, connect straight to PC com port|
|3||serial out||RS232 data, connect straight to PC com port|
|5||headphone select||ground this pin to disable internal beeper and send audio out connector instead|
|6||left audio||for the firmwares mp3/ogg player, of course|
|7||right audio||and the waypoint voicenote feature, too|
The PC-DI7 cable uses four pins, but doesnt bring out the audio connections for simultaneous use as an audio player.