The installation instructions provided with your NMEA^® 0183 compatible device should contain the information you need to identify the transmitting (Tx) and receiving (Rx) A (+) and B (-) wires. Each port may have one or two transmitting wires, or one or two receiving wires.

When connecting NMEA 0183 devices to ports containing two transmitting (Tx) wires or two receiving (Rx) wires each, it is not necessary for the NMEA 0183 device to connect to a common ground.

When connecting a NMEA 0183 device to ports containing one transmitting (Tx) wire or one receiving (Rx) wire each, the NMEA 0183 device must be connected to a common ground.

When the device is mounted in a location that prevents the internal antenna from acquiring a satellite signal, you can connect an external GPS 19x antenna through a NMEA 0183 connection. For more information, see the GPS 19x Installation Instructions.