NMEA 0183 uses RS-422 balanced differential pairs at 4800 or 38400 baud for serial communication between marine instruments like GPS VHF radio autopilot and AIS using a simple 2-wire or 3-wire connection.
| Pin | Name | Function | Type |
|---|---|---|---|
| TX+ | TX+ | NMEA talker transmit positive | BUS |
| TX- | TX- | NMEA talker transmit negative | BUS |
| RX+ | RX+ | Receive positive from talker | BUS |
| RX- | RX- | Receive negative | BUS |
| GND | GND | Signal ground | GND |