Piedinature - Pinouts
Lowrance AirMap, AirMap 300, GlobalMap 12, GlobalMap Sport

Reference and Sources:

Lowrance serial connector (6PIN)
Pin connector as seen from back of unit

Pin	Name	Description
1	GND	Ground
2	VCC	Power
3	TX	NMEA/Pseudo RS-232 (transmit serial)
4	RX	RS-232 (receive serial)
5	-	DO NOT USE
6	-	DO NOT USE

Piedinature - PinoutsLowrance AirMap, AirMap 300, GlobalMap 12, GlobalMap Sport