Connect Miniplex-2USB with GPSNavX/MacENC

Multiplexer Miniplex-2 USB (¹) by ShipModul company can connect all the instruments on board directly to a USB connector on your Mac. GPSNavX and MacENC software can receive and display NMEA instruments, and if necessary forward to an autopilot, a VHF DSC, chartplotter, a Radar or any other repeater.

A utility "Miniplex2" to configure the input channels and output device, choose from several operating modes, and offers advanced options for complex installation.

For a conventional implementation is quite simple, and Miniplex2 Help in French is integrated into software for detailed explanations of the various options available. Follow the guide…


The diagram below shows a typical installation :

In this example, connections (²) are as follows :

NMEA inputs (1 single instrument each connector)

  • IN1 = AIS
  • IN2 = GPS
  • IN3 = Navigation system, or any NMEA device
  • IN4 = VHF DSC

Explanations :

  • The AIS sends target data to the software on the Mac.
  • The GPS sends location data to software on the Mac and other instruments connected (VHF, Radar, Navtex, etc) .
  • The navigation system, or any other instrument, sends its data to the software on the Mac and other instruments connected.
  • VHF will send the position of a distress call to the software on the Mac, which will automatically create a waypoint from this position.

NMEA output (until 4 instruments each connector)

  • OUT1 = Autopilot
  • OUT2 = Radar, repeater, other.


  • The autopilot receives the data and NMEA position data from the active waypoint combined by the software on the Mac. In navigation mode, it will steer to active waypoint.
  • Other connected instruments will receive NMEA data from input (IN1 to IN4).

Power supply

  • The Miniplex-2USB is not powered by the USB connector. It must be powered by the onboard supply (8-35V), the connector is protected against reverse polarity.

Settings Miniplex2

The configuration utility Miniplex2, Once the multiplexer connected with the USB cable to the Mac (³), displays information about the port and the equipment characteristics : version and serial number.

configuraion miniplex 2

By checking the option " AIS " input IN1 is allocated first to the AIS at 38400 baud. All other input and output channels are to be set at the speed of 4800 baud. The "NMEA Mode Out2" lets you choose between 3 modes : Server, Hub or Auto. Consult’Miniplex2 Help for details of how. In this case, the mode is set to Hub. If any you want to connect a chartplotter, these devices generally accept a transfer speed up 38400 baud to receive data from an AIS. It will then adjust the speed of the output OUT2 to 38400, the mode Hub, and preferably connect other instruments to OUT1 (4800 baud) in addition to the autopilot.

seatalkIf you connect to input a network Raymarine SeaTalk, you have to check the "Conversion Seatalk", that will enable conversion of SeaTalk data to NMEA data to input IN4, and will lock the speed at 4800 baud. You connect the SeaTalk son of respecting the diagram against.

Finally I do not recommend, at least understand what you are doing, you get into the advanced options, as NMEA sentences filter, the risk of losing some data from your instruments. But, don't worry, this is not irreversible !

Once connections are done, instruments and settings enabled, you will see in the window scroll sentences flowing through the multiplexer. You quit Miniplex2 Utility (imperative before launching the charting software).

Settings in GPSNavX or MacENC

You launch the application, then you open the window Instruments :

réglages instrumentsYou check "Use the GPS port". Then, open GPS :

réglages gps

The as depends on whatever you have connected, Furuno here, the port is the Miniplex2, you select "Repeat to" and "Auto Pilot" to send only data on autopilot (on OUT1). You will see, in the window "Monitor" green scroll the sentences received, yellow one referred to those send to autopilot.

Your setup is complete. The accompanying User Manual in French Miniplex2 provides additional information about using this device in detail all the possible options for responding to more complex installations.

Article produced with the kind assistance of François Bailly-Comte aboard "Gastibelza".

(¹) See dedicated page on my website to find all prior information regarding the multiplexers.

(²) View tutorial NMEA wiring.

(³) Must first have installed the FTDI driver available for download from my website.


4 Replies to “Connect a Miniplex-2USB with GPSNavX / MacENC”

  1. Thank you for all this valuable information.
    In case the GPS data from a GPS antenna connected directly to a USB port on the Mac, the scheme is still valid and functional?
    Peut-on Brancher a loch speedo Raymarine ST 40 directly without passing through the multiplexer interface SeaTalk / NMEA / comp?
    Again, thank you

    1. For GPS, Yes, in this case it creates two serial ports on the Mac. It usually takes first connect the GPS, Then the Miniplex. This is the Mac that will send all data to outputs 1 and 2.
      For ST40, yes, login as described in the article.

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