| bottom of the unit Pin | Pin Name | Description |
| 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 |
| 4 | ground | signal ground |
| 5 | headphone select | ground this pin to disable internal beeper and send audio out connector instead |
| 6 | left audio | for the firmware"s mp3/ogg player, of course |
| 7 | right audio | and the waypoint voicenote feature, too |
The PC-DI7 cable uses four pins, but doesn"t bring out the audio connections for simultaneous use as an audio player.