NMEA 0183 Multiplexers for Marine Electronics Data Integration

Originally developed to consolidate serial data from various onboard systems, NMEA 0183 multiplexers streamline the management of sensor outputs such as GPS, AIS, sonar, depth sounders, and wind instruments, feeding this information into displays, autopilots, and other control units.

Jump to section:

• What is a Multiplexer?
• Functionality and Types of NMEA 0183 Multiplexers
• Transitioning from NMEA 0183 to NMEA 2000
• Applications and Benefits of NMEA 0183 Multiplexers

What is a Multiplexer?

NMEA 0183 Multiplexer for Marine Electronics by Actisense

A multiplexer is a device that combines multiple input signals into a single output, allowing various data sources to communicate over a shared connection. In marine electronics, an NMEA 0183 multiplexer consolidates input from several NMEA 0183 devices and ensures that all information reaches its destination without data conflict or loss. This is particularly useful in systems with limited data ports or when multiple instruments need to send data to a central processor or chartplotter.

For example, a vessel might use a GPS receiver, depth sounder, and AIS transponder—all outputting NMEA 0183 data. An NMEA 0183 multiplexer collects these individual data streams, filters and prioritizes the messages, and transmits them via a single serial output to an autopilot or multifunction display. This eliminates the complexity and risk of wiring each device independently.

Functionality and Types of NMEA 0183 Multiplexers

NMEA 0183 multiplexers are available in various configurations depending on the number of data inputs and outputs required. Basic models may support 2 to 4 input channels, while more advanced multiplexers can handle up to 8 or more. Many models now feature bi-directional ports, allowing for both data reception and transmission (TX/RX), enabling interactive communication between systems.

Key features often include:

• Baud rate control for compatibility with different devices
• Configurable data filters to exclude unnecessary NMEA sentences
• Electrical isolation to protect connected equipment
• Wi-Fi or Ethernet capabilities for wireless data transfer
• Support for multiple output formats or conversion to NMEA 2000

A popular example is a serial NMEA 0183 multiplexer hub with 4 input channels, configurable filtering, and one bi-directional output. Some variants offer NMEA 0183 Wi-Fi multiplexers, enabling remote access to instrument data on tablets or smartphones via dedicated apps or web interfaces. These are especially useful for recreational sailors and survey teams conducting mobile operations.

Transitioning from NMEA 0183 to NMEA 2000

While NMEA 0183 remains widely used, particularly on legacy systems and smaller vessels, the marine industry is gradually shifting to NMEA 2000—a faster, more robust, and plug-and-play protocol. However, the transition is not always immediate or complete. Many vessels operate hybrid networks where both NMEA 0183 and NMEA 2000 devices coexist. In these situations, NMEA 0183 multiplexers play a bridging role.

Certain multiplexer models now support data conversion, allowing NMEA 0183 data to be translated and forwarded to NMEA 2000 backbones. For instance, a NMEA 0183 to NMEA 2000 multiplexer can take GPS and AIS data in 0183 format and make it available on a 2000 network for newer instruments. This allows vessels to retain legacy devices while gradually adopting NMEA 2000-compatible systems.

The ability to integrate different data sources is particularly important in applications such as:

• Commercial fishing vessels integrating catch data, navigation, and sonar inputs
• Oceanographic research vessels requiring synchronized sensor data logging
• Unmanned surface vessels (USVs) using multiple sensor types for autonomous navigation

In such cases, data select features and message filtering ensure only the most relevant NMEA messages are forwarded to critical control systems.

Applications and Benefits of NMEA 0183 Multiplexers

NMEA 0183 multiplexers are used across a wide spectrum of marine sectors, including commercial shipping, scientific research, and defense. Their primary advantage is efficient data management, enabling real-time sharing of information between devices without overloading communication channels.

Multiplexer for NMEA 0183 Devices by Actisense

Some specific use cases include:

• Feeding GPS and heading data to both radar and autopilot systems simultaneously
• Routing AIS and wind sensor data to an onboard computer for navigation software
• Connecting multiple echo sounders to a single display unitLogging environmental data from various NMEA sensors for post-mission analysis

The use of multiplexers also helps future-proof a vessel’s electronic suite. By simplifying data routing and enhancing compatibility between older and newer equipment, they reduce the need for full system overhauls when upgrading select components.

As marine electronics evolve, NMEA 0183 multiplexers remain a fundamental tool for ensuring interoperability between diverse onboard systems. From simple data consolidation to complex signal filtering and NMEA 2000 conversion, these devices provide a reliable, adaptable solution for managing marine sensor data.