NDCU - Navigation Data Computing Unit

NDCU - Navigation Data Computing Unit is a universal device to receive and transmit RS422 signals such as NMEA 0183, Course Bus or other similar serial protocols with baud rate up to 115200 bps. The device is equipped with four independent serial inputs and four independent serial outputs, USB port which can be used not only for configuring the device but also for listening of the signals, and a fully configurable relay.

Depending on the software uploaded by the user it allows to simple manipulate, filter, combine NMEA strings, making calculations and changing NMEA talkers or even protocols!


  • Multipurpose, flexible device
  • Simple and compact design
  • Easy installation on the DIN rail
  • Each NMEA input is separated from other connected NMEA devices
  • Four inputs with separately configurable baud rate
  • Four outputs with two channel buffers – so two receivers can be safely connected to each output
  • Standard USB port for programming the device or listening signals
  • Fully configurable relay (alarm, BNWAS reset or any other purpose)
  • Software upload by USB port and standard PC computer

Technical data:

  • Power Supply: 24VDC (9 to 36VDC)
  • Power consumption: maximum 7,5 W at 24VDC
  • Number of inputs: 4, baud rate configured separately
  • Number of outputs: 4 the same baud rate as a relevant input
  • Input/output signal baud rate: 2400 – 115200 bps (230400 bps as output only) compatible with IEC 61162-1, IEC 61162-2
  • Connection: cables diameter up to 1,5mm2
  • Dimensions: L 92,0 mm x W 86,4 mm x H 72,0 mm
  • Mounting: DIN Rail.
  • Data retention: 20 years at 85 °C / 100 years at 25 °C
  • Galvanic isolation: Power supply 1,5kVDC, signal input/output up to 5kVRMS

Need custom software? Please contact info@boolean.pl

Software available:

HDC - Heading Data Converter software based on NDCU - Navigation Data Computing Unit hardware has been designed to convert gyrocompass serial heading to other desired serial format. Software version 1.0.0 allows to convert Raytheon Anschutz Cursebus (STD20, STD22) data into IEC 61162-2 NMEA Superfast (50Hz) 38400 bps. Unit has preconfigured input/output baud rate and operates with power supply range from 9 to 36 VDC. NDCU transmits HEHDT and HEROT telegrams every time once Cursebus telegram has been received. With not interrupted Cursebus transmission NMEA telegrams are transferred 50 times per second, so exactly the same rate as Raytheon Anschutz telegrams.

True Wind Calculator software based on NDCU (Navigation Data Computing Unit) hardware has been designed to calculate True Wind Angle and Speed. Once MWV (Relative Wind) is received and Gyro with GPS signals are valid, system will transmit calculated MWD or MWV (True Wind) string immediately after. True Wind transmission frequency is related to received MWV (Relative Wind) telegrams. If Wind Sensor transmits MWV telegrams with frequency 5Hz (5 times per second) system will retransmit then with the same frequency together with calculated True Wind telegrams for every received MWV string.

GPS Speed Converter software based on NDCU (Navigation Data Computing Unit) hardware has been designed to convert GPS speed telegram (VTG or RMC) to speedlog NMEA telegram (VBW or VHW) .Once VTG or RMC is received system will transmit converted VBW or VHW string immediately after. Output string telegram is to be configured during commissioning.

Multiplexer / Demultiplexer software based on NDCU (Navigation Data Computing Unit) hardware has been designed to combine up to 4 NMEA inputs and transmit all of them through one output. Transmitted and received signal is galvanically isolated from each other, power supply and all listeners. Multiplexer has configurable input and output baud rate separately for each input. Only baudrate of input 4 is combined with multiplexer output. Telegrams can be filtered, therefore it is possible to limit transmitted strings only to most important to avoid overloading of output line in slow baud rate mode. User can define manually which string will be forwarded. Unit can operate with signal baud rate from 2400 to 115200 bps and power supply range from 9 to 36 VDC.

The biggest advantage is Demultiplexer option what gives possibility to transfer all important strings in example from Navigation Bridge to Engine Room over only one pair of wires and split them back to 4 lines even with higher or lower baud rate!

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