| Feature | NMEA 0180 | NMEA 0183 (original) | | :--- | :--- | :--- | | | Unidirectional (simplex) | Bidirectional (half-duplex) | | Baud Rate | 1200 fixed | 4800 (later variable up to 115200) | | Talkers | One per line | Multiple (via multiplexers) | | Listeners | Up to 3-4 practical | Up to 10-15 practical | | GPS Support | No | Yes (GGA, RMC, GLL sentences) | | Acknowledgment | None | Basic (ACK/NAK in later versions) | | Standard Connector | No | Yes (DB-9 recommended) |
| Sentence | Description | Example Data | | :--- | :--- | :--- | | | Depth | Water depth below transducer | | DBT | Depth Below Transducer | Similar to DPT but with different units | | VLW | Distance traveled through water | Cumulative and trip log | | VHW | Water speed and heading | Speed (knots) and heading (degrees) | | RMA | Recommended minimum LORAN-C data | Position, time, speed, course | nmea 0180
Introduction Before the blue glow of multifunction displays and high-speed NMEA 2000 networks, there was a noisy, slow, and revolutionary protocol: NMEA 0180 . While most boaters and marine electronics technicians are familiar with its successor, NMEA 0183, few remember the standard that started it all. NMEA 0180 was the marine industry’s first serious attempt to standardize digital communication between onboard electronic instruments. | Feature | NMEA 0180 | NMEA 0183
Introduced in the early 1980s by the National Marine Electronics Association (NMEA), 0180 was designed to solve a simple but frustrating problem: depth sounders, lorans (pre-GPS navigation systems), and speed logs from different manufacturers could not share data. NMEA 0180 changed that, laying the groundwork for the integrated helm stations we take for granted today. Introduced in the early 1980s by the National