I'm not sure if I totally understand your question. But I just tried the following tests between my laptop and the gps:
Pins 2,3,5,9 straight-thru, no batteries: doesn't work
Pins 2,3,4,5,9 straight-thru, no batteries: doesn't work
Pins 2,3,5,9 straight-thru, with batteries: doesn't work
Pins 2,3,4,5,9 straight-thru, with batteries: works
Pins 2,3,4,5 straight-thru, with batteries: works
Pins 2,3,5 straight-thru, 6v to pin 4 with batteries: works
Pins 2,3,5 straight-thru, 6v to pin 4 no batteries: doesn't work
Pins 2,3,5 straight-thru, 6v to pin 9 with no batteries: doesn't work
Pins 2,3,5 straight-thru, 6v to pin 4 and 6v to pin 9 with no batteries: works