MiniPlex-3 firmware changelog

Version Date Description
2.2.2 04-09-17

New Features

Vessel speed
NMEA 0183 sentence VBW is now converted in NMEA 2000 PGN 130578 and vice versa. These contain water and ground referenced vessel speeds in longitudinal and transversal directions.


GPS resolution
The resolution of latitude and longitude of NMEA 0183 and NMEA 2000 position data has been increased from 3 to 5 decimals, which equals a resolution of appr. 2 cm.

NMEA 0183 GPS sentence decoding
Until now, V2 firmware only decoded the NMEA 0183 RMC sentence in full while only reading unique fields from GLL, GGA, VTG and ZDA not present in RMC. This resulted in incomplete or no GPS data being transmitted on NMEA 2000.
This version decodes all of these sentences again.

System time
Improved handling of system time received from all protocols.

Navigation data
With an activated waypoint, plotters and navigation software output different sets of navigation parameters to control an autopilot. Handling these differences has been greatly improved.

NMEA sentence length
The NMEA 0183 standard specifies a maximum sentence length of 82 characters. Some devices however transmit sentences longer than 82 characters. The MiniPlex already accepted sentences up to 100 characters but due to market demand, this limit has been increased to 124 characters.

Bug Fixes

MiniPlex-3xx-N2K not detected by chart plotters on NMEA 2000 networks
In a setup with just a MiniPlex-3xx-N2K and a chart plotter on an NMEA 2000 network, the chart plotter would not receive any data of the MiniPlex when they were powered up simultaneously. Neither would all of the inputs of the MiniPlex be visible in the Device List on the chart plotter. After restarting the MiniPlex by either a reset command or changing any of the Device Type settings on the NMEA 2000 page, everything would be working fine again.

AIS NMEA 0183 to NMEA 2000
AIS message types 2 and 3 were not converted from NMEA 0183 to NMEA 2000.

NMEA 0183 DBT sentence
Whereas a DPT sentence generated from NMEA 2000 or SeaTalk data would be routed just fine, when set to DBT, this sentence would not be routed at all.

NMEA 0183 VLW sentence from SeaTalk
When receiving trip- and total log data from SeaTalk, the MiniPlex would occasionally output empty VLW sentence. This has been fixed. The VLW sentences are not output continuously though, since this information only appears on the SeaTalk bus once every 30 seconds to once every 1.5 minute, depending on the boat speed. Every time this information is received, the MiniPlex will transmit a VLW sentence for 15 seconds.

COG Magnetic in NMEA 0183 VTG sentence
The COG Magnetic field of a VTG sentence generated from NMEA 2000 contained a random value when no magnetic COG was received from NMEA 2000.

System time
Corrected an error in reading the year field of a ZDA sentence.

NMEA 0183 APB/RMB sentence decoding
Sentences with valid status flags but empty data fields are now handled correctly.

SeaTalk datagram 85 - Navigation data
This datagram now correctly flags valid BTW, DTW and XTE values. Raymarine displays no longer show erroneous values like 409.6 and 40.96 if this information isn't available.

AIS conversion
AIS sentences converted from NMEA 0183 to NMEA 2000 appeared on the NMEA 2000 network originating from the wrong NMEA 0183 input of the MiniPlex. This has been fixed.

2.0.6 30-05-17

New Features

High speed GPS output on NMEA 0183
NMEA 0183 sentences GGA, GLL, RMC and VTG can now be output at 10Hz, matching NMEA 2000 PGN 129025 - Position, Rapid Update. This option can be enabled by checking "10Hz" in the "NMEA 0183 Generation" section of MPX-Config3 V2.4.2.

Bug Fixes

Magnetic variation in RMC sentence
The variation field of an NMEA 0183 RMC sentence generated from NMEA 2000 or SeaTalk data contained a value of 327.67° when no variation was received from either protocol.

The priority sentence ($PSMDPR) read from the MiniPlex contained a erroneous character, causing MPX-Config3 V2.4.0 to lock up. This has been fixed in the firmware and in MPX-Config3 V2.4.1.

2.0.4 24-05-17

NMEA 2000 Certified firmware

As of version 2.0, the MiniPlex-3 firmware is NMEA 2000 certified. Every MiniPlex-3 will be an NMEA 2000 certified product when this firmware is loaded.

New NMEA 2000 Features

Virtual devices
Each input of the MiniPlex-3 now appears on the NMEA 2000 network as a unique (virtual) device. When two NMEA 0183 inputs receive similar data like position from a GPS and an AIS, this will now appear on the NMEA 2000 network as originating from two different devices instead of one.

NMEA 2000 Device Type
Each NMEA 0183 input can be set to appear as a specific Device Type on the NMEA 2000 network. A VHF radio on the NMEA 2000 network should now accept GPS position from the MiniPlex-3 when the corresponding NMEA 0183 input receiving this GPS data is set to "Ownship Position (GNSS)". Some VHF radios were known to refuse GPS position originating from a generic "NMEA 0183 Gateway" device.

Waypoints sent from navigation software to the MiniPlex-3 using $--WPL sentences are now translated to PGN 130074, enabling NMEA 2000 connected plotters to receive them.

Improved reception of NMEA 2000 GPS data
Some Simrad plotters do not send PGN 129029 (GNSS Position) which contains key-information for the MiniPlex-3 to generate GGA, GLL and RMC sentences. Instead, these plotters only send PGN 129025 (Position, Rapid Update) which does not contain any information about the GPS mode and fix-quality. The MiniPlex-3 will now decode this PGN too and simulate status and mode flags in the GGA, GLL and RMC sentences.

NMEA 2000 data converted to NMEA 0183 can now be routed based on the Source Address of an NMEA 2000 device. This allows selective routing of similar data from different devices. This way, the position data from an AIS can be blocked while passing it from a GPS.

New SeaTalk Features

It is now possible to selectively route NMEA data to the SeaTalk bus. No data is sent to SeaTalk by default anymore.

Autopilot Control
Navigation data from NMEA 0183 or NMEA 2000 can now be routed to the SeaTalk bus to control an autopilot. Waypoint names are also converted to SeaTalk and will appear on SeaTalk repeaters.

GPS Mode
The GPS mode/status on the SeaTalk bus is decoded now to reflect the GPS status in the converted NMEA 0183 and NMEA 2000 data.

General Processing

In previous firmware versions, received data was stored in input-queue's and routed from there to the various outputs. The slowest output determined the overall data throughput to prevent any data loss on the outputs. This could could in turn cause any input queue to overflow and loss of data on all outputs.

In V2.0 the input queue's have been removed. Instead, each NMEA 0183 output now has a buffer capable of holding one second of data at 4800 Baud. Each NMEA sentence is now immediately routed to the outputs when received. The result is that if a "slow" output cannot keep up with the "feed", only this output will loose data. All others, including the USB, Ethernet and WiFi interfaces, will no longer loose the same data. This has improved the overall throughput of the MiniPlex-3 dramatically.

1.18.0 16-01-17

Bug Fixes

The system time is no longer set from a GNSS (GPS) source when it has no position fix.


Depth Sentence
An option is added (option/bit 19)) to change the $SDDPT sentence generated from SeaTalk or NMEA 2000 to a $SDDBT sentence. This option can be enabled by typing PSMDOP,C,19,1 in Manual NMEA Sentence Input in MPX-Config3

Conversion added from PGN 127252 (Heave) and PGN 127257 (Attitude) to Furuno’s proprietary NMEA 0183 sentences $PFEC,GPhve and $PFEC,GPatt.

1.17.3 08-12-16

Bug Fixes

A bug has been fixed which caused two or more MiniPlex-3E(-N2K) multiplexers on the same network to lock up if the configuration was read from one multiplexer. The other(s) would respond to the $PSMDVER sentence sent by the first with their respective $PSMDVER sentences and each would continue to invoke a response from the other.

1.17.2 22-09-16

Bug Fixes

Water Depth received from SeaTalk was not converted to NMEA 2000. This is fixed.

1.17.1 08-09-16

Bug Fixes

A bug has been fixed that could lock up the MiniPlex when it received too much NMEA data through the host interface. This particularly affected the MiniPlex-3E(-N2K) set to UDP broacast, on a network with other multiplexers which also sent NMEA data using UDP broadcast.

1.17.0 01-09-16


Adrena/NKE support
Adrena navigation software uses NKE proprietary sentences ($PNKEA…) to control the layout on NKE displays. These sentences contain so called Extended-ASCII characters like the degree-sign (°) which are not supported by the NMEA 0183 standard. These Extended ASCII characters are no longer blocked by the MiniPlex.

Bug Fixes

AIS Class B targets
The MiniPlex-3 firmware is based on NMEA 2000 standard V2.0. However, many AIS transponders still use NMEA 2000 V1.3.

PGN’s 129809 and 129810 (Class B Name and Static Data) received in V1.3 format were not converted to NMEA 0183. This mainly affects Raymarine AIS transponders. This version now correctly converts these PGN’s into NMEA 0183 sentences.

1.16.0 18-08-16


  • An automatic Device Instance filter ensures that similar PGN's from multiple sources are converted only from the source with the lowest Device Instance number. In a later version, it will be possible to filter on Device Instance through the sentence Filter.
  • The divisor in the Sentence Filter now only affects routing to the NMEA outputs. Routing to a host port always occurs at the original frequency.
  • When navigating a route, the origin and destination waypoint names are now also converted from NMEA 0183 to NMEA 2000 and back. It is no longer necessary to use numerical waypoint names only.

Bug Fixes

  • A bug is fixed that prevented conversion from an HDT sentence to an HDM sentence.
  • When navigation data was converted from PGN 129284 to an RMB sentence, the minutes in the longitude field of the RMB sentence were 10 times too high. This has been corrected.
1.15.0 04-08-16


  • The !AIVDO sentence (Own Ship data) is now converted from NMEA 0183 to NMEA 2000 and back.
  • Conversion of AIS Message 14 (Safety Related Broadcast message) added in both directions.
  • In NMEA 0183 AIS messages, unused positions in text fields contain a '@' character. These were replcaed with ASCII code 0xFF when converted to an NMEA 2000 PGN, which is the NMEA 2000 value to indicate unused characters. Some plotters however displayed these 0xFF as 'ÿ' characters. This firmware no longer converts the '@' into 0xFF. The NMEA 2000 standard is not quite clear on this.
  • The fixed Device Instance filter for Water Depth (PGN 128267) is improved. Previously, only depth from sensors with Device Instance 0 (the default value per NMEA 2000 standard) was converted.

    On SeaTalk NG networks however, depth sensors have a (arbitrary?) non-zero Device Instance which cannot be changed. This effectively inhibits conversion to NMEA 0183 in the MiniPlex.

    This is now solved with a dynamic Device Instance filter, converting PGN 128267 from the lowest Device Instance only when received from multiple devices.

Bug Fixes

  • Fixed errors in calculation AIS target sizes.
1.14.7 06-07-16


  • Full conversion of AIS Class A and B targets from NMEA 0183 to NMEA 2000 and vice versa
    The following AIS messages are converted:
     • Class A: messages 1, 2, 3 and 5.
     • Class B: messages 18, 24A and 24B.
     • Class B: message 19 from NMEA 0183 to NMEA 2000 only.

Bug Fixes

  • AIS NMEA 0183 to NMEA 2000
     • GNSS type in message 5 was not read correctly.
     • Negative longitudes (W) and latitudes (S) were converted incorrectly.
  • AIS NMEA 2000 to NMEA 0183
     • Precision Accuracy and SOG were corrupted at negative longitudes.
     • Longitude was corrupted at negative latitudes (S).
1.14.5 30-06-16

Bug Fixes

  • Routing
    Routing of NMEA 0183 sentences appeared to be arbitrary due to an unitialized variable.
  • SeaTalk rudder angle
    The rudder angle received from the SeaTalk bus was not processed correctly, which resulted in large angles when the rudder was steering left.
  • Magnetic <-> true heading
    Compensating a heading with a magnetic variation or deviation resulted in erroneous heading values when the variation or deviation value was negative (W).


  • Partial NMEA 2000 AIS support
    Currently, the following conversion are implemented:
     • Class A targets in both directions between NMEA 0183 and NMEA 2000
     • Class B targets -position report only- from NMEA 0183 to NMEA 2000
  • Autopilot control from naviation applications
    The buffer of the host input (USB, Ethernet) is increased to 1024 bytes. With a waypoint activated, a navigation application can send many sentences at a time to the multiplexer to control an autopilot. It is then required that the application supports hardware flow control (CTS/RTS). This allows the multiplexer to temporarily suspend the flow of data when the buffer in the multiplexer is almost full. Unfortunately, not all applications support this. The increased buffer size prevents overflow in such cases.
  • Improved autopilot control from NMEA 2000
    PGN 129284 (Navigation Data) now has field 6 (Calculation Type) set to 0, indicating Great Circle calculations. Neither the APB nor the RMB sentence contain the calculation type so Great Circle is assumed by default because this corrects for kong legs and has the smallest error on short stretches.
    Also, fields 3 (Course/Bearing Ref.), 4 (Perpendicular Crossed) and 5 (Arrival Circle Entered) now keep their contents when being transmitted. In previous versions, these fields were overwritten with a "Not Available" status by some plotters when no waypoint was activated in the plotter.
  • NMEA 2000 Device Instance
    It is now possible to remotely change the Device Instance of the multiplexer. Many chart plotters offer the posibility to list all connected NMEA 2000 devices and to assign a Device Instance to a connected device. This allows selecting data from multiple devices of the same kind. This will now work for multiple NMEA 2000 enabled multiplexers too.
  • Fixed filter for NMEA 2000 Water Depth from Device Instance 0
    A built-in filter only passes PGN 128267 (Water Depth) from devices with Device Instance set to 0. Many superyachts employ two sounders, one near the bow and one aft, at the rudder. The hard-coded filter allow selection of which sounder data to pass.
    At a later stage, we will add a Device Instance column to the Sentence Filter.
  • Transmission of NMEA 2000 Heatbeat message
    NMEA 2000 enabled multiplexers now send PGN 126993 (NMEA 2000 Heartbeat message) onto the NMEA 2000 bus every minute.
1.13.3 28-04-16

Bug Fixes

Corrected the following errors in converting an RMB sentence to NMEA 2000:

  • PGN 129283 (Cross Track Error)
    The XTE value was wrong for negative (Steer Right) numbers.
  • PGN 129284 (Navigation Data)
    The Distance to Waypoint field was 100 times to small.
1.13.2 25-04-16

Bug Fixes

The following problems have been resolved:

  • SeaTalk
    SeaTalk datagrams 84 and 9C (heading from autopilot) are now converted to NMEA again. They were removed in V1.13.1 because of ambiguities in the format description of these datagrams.
  • NMEA 2000
    Conversion of PGN 130314 (Actual Pressure) contained an error, resulting in an MDA sentence with a pressure value 10 times lower. This has been corrected.
  • NMEA 2000
    When the MiniPlex received an RMC sentence with empty magnetic variation fields, the sentence was not converted into NMEA 2000.
  • NMEA 2000
    Values in NMEA 0183 sentences with a leading '+' sign were incorrectly read. This occured for instance with a VDO Depth sensor, which outputs positive offsets with a '+' sign in its DPT sentence.
    Formally the NMEA 0183 standard only allows a '-' sign for negative values, positive values should not have a sign. Our firmware did not check for a '+' sign. This has been added now.
1.13.1 05-03-16

Bug Fixes

  • This firmware tells MPX-Config3 about the SeaTalk transmit capability, so MPX-Config3 will now enable/display a ST column on the output side of the Sentence Filter & Routing list.
  • A bug has been fixed that locks up the MiniPlex when the WiFi connection breaks due to low signal levels or interference.
1.13.0 29-02-16


Transmission of the most common SeaTalk1 datagrams has been implemented. See the SeaTalk page for an overview of which data is received and transmitted. Currently, autopilot control ($--RMB sentence) is not implemented. We will add this in a future firmware update.

NMEA 2000 -> NMEA 0183 Conversion

Heading conversion is improved: NMEA 0183 sentences HDG, HDT and THS are now output at 10Hz when the heading source is NMEA 2000. In case of SeaTalk, these sentences are output at 2Hz, which equals the update rate on the SeaTalk bus.

1.10.0 14-10-15

New Features

The following conversions are added:

  • RMC to ZDA: The time and date of an RMC sentence are used to generate a ZDA sentence.
  • VTG to HDT: When a VTG sentence is received, the multiplexer generates a HDT sentence.


Versions are numbered as 'Vm.n.p'. These numbers have the following meaning:


Major version number. This number changes when significant improvements to the firmware are made.


Minor version number. This number changes when small features are added to the firmware.


Patchlevel number. This number changes when bugs are fixed. The feature set remains the same.

When 'm' or 'n' are changed, a new manual will be available as well as a new matching version of MPX-Config.