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NDC-4 NMEA Multiplexer
Combine multiple sources of NMEA 0183 data into a single stream.
Flexible and powerful enough to be the heart of a simple system, or one of many Actisense products in a more complex system.
The Actisense NDC-4 allows up to five NMEA 0183 sources to be multiplexed into a single stream*.

Two flexible ISO-Drive outputs allow two different downstream talker baud rates to be created, ensuring maximum system flexibility.

It provides complete access to all NMEA 0183 data sources, configurable filters to remove unwanted data using NDC Control Centre, as well as enabling an on-board PC to read and add the combined data stream.

Factory preconfigured versions enable the NDC-4 to be used out of the box for AIS operation (NDC-4-AIS). An ‘autoswitch’ option is also available (NDC-4-ASW) to provide redundancy options to your NMEA 0183 network.

*Four inputs on the USB version, as the USB interface acts as the fifth channel, overriding the fifth OPTO input.

Geek Mode
  • Multiplex up to five NMEA 0183 devices
  • Filter unwanted data leaving you with only what you need
  • Preconfigured versions for AIS (NDC-4-AIS) and Autoswitch (NDC-4-ASW) operation
  • USB option available for simple connection to a PC (NDC-4-USB)
  • USB kit (NDC-4-USBKIT) converts standard NDC-4 to an NDC-4-USB

Technical Specification

Supply ("BATT")
Voltage 8-35 V
Current   40 mA max @ 12V DC under no load
Supply (USB)
Supply voltage 4.75-5.25 V
Supply current from USB (see note 1) 75 mA max
Opto-isolated Flexible Input
Input voltage between +/- Logical ‘1’/stop bit -15-0.5 V
Logical ‘0’/start bit 4-15 V
Input current Maximum is under +35v overload condition, Min @ 2.0v input level 1.6-9 mA
Differential input voltage Required level for NMEA to be detected 1.8-2 V
Galvanic isolation Between input & output 2500 V
Overdrive protection 40 V
Input Baud rate (ports 0 & 1 + USB) Configurable Baud rate 4800-115200 bps
Input Baud rate (ports 2 & 3) Configurable Baud rate 4800-57600 bps
Input Baud rate (port 4) Fixed Baud rate 4800 bps
ISO-Drive Flexible Output
Output voltage between ISO Out +/A and ISO Out -/B (under no load) Logical ‘1’ -4.6 to -5 V
Logical ‘0’ 4.6-5 V
Output current at max load of 100 ohm At maximum load, differential drive voltage reduces to 2.1v 21 mA
Output short circuit current (note 2) Due to short circuit protection 50-55 mA
Galvanic isolation From Opto input and (USB) ground 1500 V
Output Baud rate (ports 0 & 1 + USB) Configurable Baud rate 4800-115200 bps
Data propagation delay Under no-overload conditions 1-100 ms
Ambient temperature -20-70 °C
Guarantee  Extended Actisense guarantee  3 Year
Gland clamping range Cable diameters accommodated 4.5-10 mm
IP Rating IP66
NDC-4 NMEA Multiplexer
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“I can’t stress enough how clean the Actisense products installed, the quality of the equipment and NMEA cabling, and how well everything works.”
Joe Wharton, Wharton Boatworks LC, USA
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