This Actisense™ NMEA Multiplexer / Combiner allows connection of up to five NMEA (National Marine Electronics Association) inputs, and multiplexes / combines them to its two NMEA outputs.

This approach offers these major advantages:
- Enables the vessel owner complete access to all NMEA data sources, instead of the standard one device
- Each NMEA input device is Opto-isolated from all other NMEA device in the system
- Significant reductions in installation cost (from reduced cable lengths and requiring only one NMEA cable to be routed around the bridge to supply the multiplexed NMEA data

The NDC-4 has two ISO-Drive outputs which are fully compatible with both NMEA 0183 and PC RS232 ports.

The NDC-4-USB has an additional USB bi-directional port which allows a copy of the data on the second ISO-Drive output to be sent to a virtual serial port on a PC, while receiving data from the PC through the same virtual port. This option disables the opto input reserved for the PC connection.