USB NMEA Multiplexer This Actisense NMEA Multiplexer / Combiner allows connection of up to five NMEA (National Marine Electronics Association) inputs, and multiplexes / combines or autoswitches them to its two fully isolated NMEA outputs. The NDC-4-USB model has an additional USB bi-directional port that allows a copy of the data on the second ISO-Drive output to be sent to a virtual serial port on a PC, while also receiving data (waypoint data for example) from the PC through the same virtual port. This option disables the opto input reserved for the PC connection, reducing the number of inputs the NDC-4-USB has to 4.
This approach offers these major advantages: - Completely removes the need for isolated power supplies - as the NDC-4 creates a full 2500v isolation barrier between it's inputs and each of it's ISO-Drive outputs
- Enables the vessel owner complete access to all NMEA data sources, instead of the standard one device
- Any problematic or unwanted NMEA sentences can be filtered out / blocked, to help intelligently reduce the NMEA data to a manageable amount and prevent data loops
- 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 all standards: NMEA 0183 (RS422), RS485 and PC RS232 ports.
New feature: The autoswitching feature of the NSW-1 has now been added to the NDC-4, making it the single most feature rich Multiplexer available in the marine market. The NDC-4 can either operate in 'Combine mode' as before, or the new 'Autoswitch mode' to behave like the original Actisense NSW-1 Autoswitch product. Electrical spike protection is provided as standard on all four input channels using opto-isolators. This protects any connected equipment from most system faults; a particularly valuable benefit as equipment requiring the most data, such as a PC or chart plotter, is often the most expensive to repair or replace. The NDC-4 Data Multiplexer contains intelligent software that manages the multiplexing operation, allowing every input to have a chance of its data reaching the combined NMEA output. Tested up to and beyond a combined 400% loading of the four inputs. 4-1 multiplexer - takes 4 nmea inputs and combines into single output. Useful for complex NMEA systems. Device can also be programmed by PC to mask sentences etc. | 
