See the installation instructions for the NMEA^® 0183 device to identify the transmit (Tx) A (+) and B (-) wires and receive (Rx) A (+) and B (-) wires.

Each internal Rx and Tx port has 2 wires, labeled A (+) and B (-) according to the NMEA 0183 convention. The corresponding A (+) and B (-) wires of each internal port should be connected to the A (+) and B (-) wires of the NMEA 0183 device. See the table and wiring diagrams when connecting the data cable to NMEA 0183 devices.

You must use 28 AWG, shielded, twisted-pair wiring for extended runs of wire. Solder all connections and seal them with heat-shrink tubing.

See ( Specifications) for a list of the approved NMEA 0183 sentences that are output by and input to your device.

The internal NMEA 0183 ports and communication protocols are configured on the connected Garmin^® device. See the NMEA 0183 section of the chartplotter owner's manual for more information.

The ground wires on the NMEA 0183 data cable and your NMEA 0183 device must both be connected to ground.

When connecting NMEA 0183 devices with two transmitting and two receiving wires, it is not necessary for the NMEA 0183 devices to connect to a common ground.

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

For two-way communication with a NMEA 0183 device, the internal ports on the NMEA 0183 data cable are not linked. For example, if the input of the NMEA 0183 device is connected to the internal output port 1 on the data cable, you can connect the output port of your NMEA 0183 device to any of the internal input ports (port 1, port 2, port 3, or port 4) on the wiring harness.

There are four internal NMEA 0183 input ports (Rx ports), and two internal NMEA 0183 output (Tx ports) on the included NMEA 0183 data cable. You can connect one NMEA 0183 device per internal Rx port to input data to your Garmin device, and you can connect up to three NMEA 0183 devices in parallel to each internal Tx port to receive data output by your Garmin device.