Connecting Phillips Navigator MK8 to a MT500 DSC/VHF

Philips MK8After a recent correspondence via this blog, I thought it would be useful to publish the interface information for this connection.

The Philips MK8 has two cables both with shields BUT the shields will only be connected at one end – this is the clue. So at the MK8 end there is a D-SUB 9 pin connector – open it up and have a look at the wiring….it is wired as follows:



Pin 3 – Red – NMEA OUT (to a listener)
Pin 8 – Black – NMEA OUT (to a listener)
Shield – connected to MK8 shield
(DO NOT connect the shield at your Listener end)

Pin 2 – Red – NMEA IN (from a Talker)
Pin 7 – Black – NMEA IN (from a Talker)
Shield – NOT connected to MK8 shield
(DO connect the shield at your Talker end)


Connect to Phillips Mk8
1 Brown – INPUT DC + <<<<———- signal from Pin3 RED wire on MK8
2 Red – INPUT DC – <<<<———- signal from Pin8 BLACK wire on MK8

Connect to PC – Serial cable
3 Orange NMEA OUTPUT +
4 Shield NMEA OUTPUT –

Connect to Flash programmer
5 Green – Clock
6 Blue – Reset
7 Grey – PDI
8 Purple – PDO

Now to the NMEA Protocol

If you have done any research you will have realised by now that the NMEA protocol is really a very poorly implemented “standard” . What you have discovered about the wiring carries on into the programming of the chips that send the data. This standard is the NMEA 0183 protocol – now replaced by NMEA 2000 – which is also badly implemented. Just in case you are asking why – it is because manufacturers have used this confusion to protect market share and make their equipment incompatible on purpose.

NMEA 0183 version 2.0 sentences for GPS all start with $GP and then a 3 letter acronym.

$GP*** Sentence Titles
APA: Autopilot Sentence “A”
APB: Autopilot Sentence “B”
BOD: Bearing, Origin to Destination
BWC: Bearing and Distance to Waypoint, Great Circle
GGA: GPS Fix Data GLL: Geographic Position, Lat/Long
GSA: GPS DOP and Active Satellites
GSV: GPS Satellites in view RMA: Recommend minimum Specific Loran-C Data
RMB: Recommend Minimum Navigation Information
RMC: Recommend Minimum Specific GPS/TRANSIT Data
ROO: Waypoints in Active Route (not in standard)
RTE: Waypoints in Active Route or GOTO
VTG: Track Made Good and Ground Speed
WCV: Waypoint Closure Velocity
WPL: Waypoint Location
XTE: Cross-Track Error, Measured
ZTG: UTC & Time to Destination Waypoint

So you can see that when the MT-500 DSC manual says $GPRMC / GGA they mean that the two sentences above must be being sent by the Phillips MK8.

The Phillips MK8 does comply with NMEA 0183 version 2.0 (January 1992 standard)

It will transmit RMC (Time, date, position, course, and speed data) every 2 seconds.

BUT it will also transmit GGA – Global Positioning System Fix data (Time, position, fix) if you have the MK8 with differential software. This was issued as a software upgrade after the MK8 started shipping.


5 thoughts on “Connecting Phillips Navigator MK8 to a MT500 DSC/VHF

  1. Following on from Tony Hughes question below – firstly here is the spec for the MT500 that Tony refers to.

    As for how to connect it up to the MK8 I have written a new post above to document all the tips about the wiring that I have come across, including the advice on connecting the MT500 and a Phillips MK8.

    MT500The MT-500 is the latest Class-D DSC equipped marine VHF from M-TECH. It meets the EN-301 025 capabilities with integral CH70 watch receiver.

    Position Send/Request functions are also included which enable you to transmit/request the position data to other vessels. The received position data is transferred to a connected plotter (not supplied), if your plotter is DSC capable.

    Large SELECT/ENT knob can be rotated and pushed which offers you simple and easy operation for channel and menu selection.

    Construction is waterproof meeting the JIS-7 standard

    • Built-in CH70 watch receiver
    • 32 MMSI number directory
    • Large dot-matrix LCD display – 4 lines with 11 characters each
    • LAT/LON position indication with GPS connected
    • Alert for GPS unconnected
    • Position Send/Request_transfer the received position data to a connected plotter
    • All available INT’L plus authorized local channels
    • 3 channel scanning modes_Priority, All and Memory Scan
      Channel name indication
    • DISTRESS button with protective cover
    • One button instant access to CH16
    • Large SELECT/ENT knob for channel/menu
    • Microphone with alphanumeric keys
    • Waterproof meeting the JIS-7 standard
    • Selectable ATIS mode for inland waterways


  2. Dear Russ,

    Can you help me with an instruction to connect an Clipper GPS repeater to a Phillips MK8 GPS?

    I try to connect them, without a good result.
    I onely get info that there is a 12V connection, but no data info.


  3. We acquired a GPS Navigator MK8 with our boat & the instructions dated July 1993 & it worked last year, but now it just shows the position as zeros or similar if you change the datum base. Have tried replacing the Back-up battery ‘expected life 2 years’. All the tests appear OK, including the antenna. Any suggestions?

  4. Dear sir, can you help.
    I am trying to connect my Garmin 450 GPS to a M Tech 500 DSC VHF Transceiver.Both unit`s wiring instructions are not clear and although I have followed them correctly, The GPS is not speaking to the M Tech vhf, with no Lat or Long readingsor time etc.
    Be grateful for advice. Are they compatible?

    Tony and Ann (United Kingdom)

  5. Hi,
    I have a Mk8 and just like Chris Woodd-Walker is has also stopped displaying Lat & Long. Is there a solution to this?

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