ShipModul MiniPlex-3 Series User manual

MiniPlex-3 series NMEA 0183/2000 multiplexer
Manual
This manual covers:
MiniPlex-3USB
MiniPlex-3USB-N2K
MiniPlex-3E
MiniPlex-3E-N2K
MiniPlex-3 series, V1.0
Firmware V1.0.x/1.9.x
Rev. C, 11-9-2015
© CustomWare, 2015

2
Introduction................................................................................................................................4!
NMEA 0183.................................................................................................................................4!
NMEA Sentences.......................................................................................................................4!
Talkers and Listeners ................................................................................................................4!
The Multiplexer.........................................................................................................................5!
The Host..................................................................................................................................5!
The MiniPlex-3 Multiplexer .........................................................................................................6!
Galvanic Isolation...................................................................................................................6!
NMEA 2000 ...........................................................................................................................6!
Feature Set ...........................................................................................................................6!
Host Port....................................................................................................................................8!
USB Port ....................................................................................................................................8!
Driver Installation ..................................................................................................................9!
Network Interface...................................................................................................................... 14!
Network Basics....................................................................................................................... 14!
IP Address .......................................................................................................................... 14!
Netmask ............................................................................................................................. 14!
Port Number........................................................................................................................ 14!
Protocols............................................................................................................................. 15!
Assigning IP addresses ............................................................................................................ 15!
MiniPlex-3E Network Setup ...................................................................................................... 16!
Search................................................................................................................................ 17!
Network Recovery ................................................................................................................ 18!
NMEA 0183 Ports....................................................................................................................... 19!
NMEA 0183 Signals ................................................................................................................. 19!
NMEA 0183 Inputs .................................................................................................................. 19!
NMEA 0183 Outputs ................................................................................................................ 20!
Combining Ports ..................................................................................................................... 21!
SeaTalk ................................................................................................................................. 21!
NMEA 2000............................................................................................................................... 22!
Connecting to the NMEA 2000 network ...................................................................................... 23!
Power Supply............................................................................................................................ 24!
Indicators................................................................................................................................. 24!
Data Throughput ....................................................................................................................... 25!
MPX-Config-3............................................................................................................................ 27!
Menu .................................................................................................................................... 28!
Controls ................................................................................................................................ 29!
MiniPlex Connection.............................................................................................................. 29!
Viewer Options .................................................................................................................... 30!
NMEA Inputs/Outputs ........................................................................................................... 31!
Options............................................................................................................................... 34!
NMEA Conversions ............................................................................................................... 35!
Wind: VWR <-> MWV ........................................................................................................... 36!
Sentence Filtering & Routing.................................................................................................. 37!
NMEA 2000 ......................................................................................................................... 40!
Firmware Update ....................................................................................................................... 41!
Procedure .............................................................................................................................. 41!
Mounting.................................................................................................................................. 42!
Technical Reference ................................................................................................................... 43!
NMEA 0183 Glossary ............................................................................................................... 43!
Talker ID’s .......................................................................................................................... 43!
Sentence formatters............................................................................................................. 43!
Supported NMEA 2000 PGN’s.................................................................................................... 45!
Translated SeaTalk datagrams.................................................................................................. 46!
Firmware Update Error messages.............................................................................................. 47!
Standard NMEA 0183 Sentences ............................................................................................... 48!
$MXSTN – Multiple Data ID ................................................................................................... 48!
$MXPGN – NMEA 2000 PGN Data ........................................................................................... 48!
Proprietary NMEA 0183 Sentences ............................................................................................ 50!
Example ............................................................................................................................. 50!
$PSMDC – Get Configuration record........................................................................................ 51!
$PSMDN – Set NMEA 2000 Configuration................................................................................. 51!
$PSMDCF – Set Configuration ................................................................................................ 51!
$PSMDDR – Set Default Route ............................................................................................... 51!
$PSMDFL – Set Filter Rules.................................................................................................... 52!
$PSMDID – Set Talker ID ...................................................................................................... 53!

3
$PSMDIN – Input options ...................................................................................................... 54!
$PSMDLDR – Loader message................................................................................................ 54!
$PSMDOP – Set Options........................................................................................................ 55!
$PSMDOV – Overflow ........................................................................................................... 56!
$PSMDRESET – Reset the multiplexer ..................................................................................... 56!
$PSMDSP – Set Speed .......................................................................................................... 56!
TAG Block ........................................................................................................................... 57!
$PSMDUI – Set Unique Identifier............................................................................................ 57!
$PSMDVER – Get Version ...................................................................................................... 57!
Technical Specifications ........................................................................................................... 58!
MiniPlex-3USB ..................................................................................................................... 58!
MiniPlex-3USB-N2K .............................................................................................................. 58!
MiniPlex-3E ......................................................................................................................... 59!
MiniPlex-3E-N2K .................................................................................................................. 59!

4
Introduction
The MiniPlex-3 series NMEA multiplexers enable the connection of multiple NMEA 0183/2000 devices and
a host device like a PC, a laptop or a tablet. All models share the same number of NMEA ports and
features. They differ in the type of host interface, the interface that talks to the computer. Some models
also have an NMEA 2000 interface.
This manual covers all models of the MiniPlex-3 series. There is a chapter for each type of host port. The
remaining part of the manual covers NMEA 0183 connections and configuration, which are the same for
all models.
We will also explain NMEA 0183 and how things connect (or not).
For all –N2K model there’s a chapter about NMEA 2000.
NMEA 0183
The NMEA 0183 Standard, a communication standard defined by the NMEA organization
(www.nmea.org), defines a communication protocol called NMEA 0183 that enables navigation
instruments and devices to exchange data with each other.
This way, a compass can send a heading to a radar to enable a north-up display, a GPS can send cross-
track and waypoint information to an autopilot in order to steer a programmed course.
NMEA Sentences
NMEA data is made up of readable text sentences. If you would connect the output of a navigation
instrument to the serial port of a computer and start a program that displays the incoming data, you
would see something like this:
$GPGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*2E
$GPGGA,143357.999,5301.0061,N,00635.5479,E,1,06,1.9,90.0,M,,,,0000*39
$GPGLL,5301.0061,N,00635.5479,E,143357.999,A*22
$HEHDT,67.0,T*1E
This is plain text in a format that is laid out in the NMEA 0183 standard. Every device that receives this
information would know that the sentence starting with GPGLL originates from a GPS (hence the GP at
the beginning of the sentence) and that it contains the geographic longitude and latitude (GLL).
The term “NMEA sentence” is used for NMEA data because it is made up of single lines of text.
Throughout this manual, “NMEA sentences” and “NMEA data” will be used randomly.
Talkers and Listeners
The NMEA 0183 standard defines talkers and listeners. A device that sends information is a talker and a
device that receives information is a listener. When connected to each other, the talker sends information
to the listener.
Communication using the NMEA 0183 protocol involves at least one talker
sending data to one listener. Figure 1 on the right shows such a minimal
system: a gyrocompass sends heading data to a radar.
It is important to know that a talker or listener port is named after its
function, not after what it is connected to. So a talker port sends out
information but it connects to a listener. This might be confusing at times so further in this manual we
will use the terms input and output instead of listener and talker port respectively.
The NMEA 0183 standard specifies that a talker should have enough driving capacity to talk to four
listeners. This is as easy to achieve as telling a story to an audience of four people - the only requirement
is to talk loud enough.
Gyro Radar
Figure 1

5
Figure 2
The left part of Figure 2 shows such a situation: one GPS sends data to four devices.
It gets complicated when several talkers must send data to one listener (the PC) as shown in the right
part of Figure 2. Unless that listener has multiple inputs, this is not possible without help.
Simply connecting multiple talkers to one listener as shown is like four people simultaneously telling you
a different story. You can make neither head nor tail of it. In electronics terms: the outputs of the talkers
will short-circuit each other and the sentences they transmit will be corrupted.
This is where a multiplexer offers the solution.
The Multiplexer
A multiplexer, sometimes called combiner, has multiple listener
ports, each acting as a listener connected to a single talker. It also
has at least one talker port that outputs the combined data from
the inputs to a listener. So what seemed impossible in Figure 2 is
possible when a multiplexer is added as shown in Figure 3. The
multiplexer listens to the instruments by storing the received
NMEA sentences into queues simultaneously. At the same time it
retrieves the sentences from the queues sequentially and sends
them to the PC.
Since a PC can do so much more than just displaying the
combined data, it soon became apparent that a multiplexer needs
more than just a few inputs and one output. The single talker port
that connects to the PC became a host port, being input and
output at the same time. A few extra talker ports made it possible
to send data to other devices and to drive an autopilot.
The Host
NMEA 0183 devices already existed before it was common practice to use a computer for navigation. Of
course there were ECDIS systems (Electronic Charting and DISplay) but these were used only on
commercial ships. Nowadays it is very common to use a computer, a laptop or a tablet as a charting
device while the navigation software sends information to an autopilot in order to automatically follow a
programmed route. This computer, laptop or tablet becomes a navigation host and what used to be a
talker port on the multiplexer is now called a host port. The multiplexer becomes the central interface
that listens and talks to all navigation instruments and devices.
Throughout this manual, the common term Host is used for a PC, laptop, smartphone, PDA, tablet or any
device that is connected to the multiplexer to send and receive NMEA data for processing and display.
The host interface or host port is the interface that connects to these devices and this can be a USB,
Ethernet or WiFi interface.
GPS
PC
VHF
Radar
Auto-
pilot
PC
GPS
Depth
Wind
Log
PC
GPS
Depth
Wind
Log Multiplexer
Figure 3

6
The MiniPlex-3 Multiplexer
The MiniPlex-3 multiplexer is an advanced NMEA 0183 multiplexer with four NMEA inputs or listener
ports, two NMEA outputs or talker ports and one or two host interfaces.
It combines NMEA sentences that are received on the NMEA
inputs and it can send these sentences to the NMEA outputs
and to the host interface(s). These host interfaces can also
be used to send NMEA sentences back to the multiplexer to
be forwarded to its NMEA outputs and to send commands to
configure the multiplexer.
Figure 4 shows a typical setup where the MiniPlex-3 is used
to combine data from four instruments, send it to a PC and,
depending on the configuration of the MiniPlex, send the
same data to an autopilot and a repeater display. The PC is
also capable of controlling the autopilot to steer a
programmed route and to display information such as
distance to next waypoint on the repeater display.
Galvanic Isolation
Every NMEA input and output of the MiniPlex-3 is galvanically
isolated, sometimes called opto-isolation because opto-couplers are used to achieve this isolation. An
opto-coupler is an electronic component that transports information by means of light instead of
electricity, thus creating a barrier for electrical currents and voltages.
Galvanically isolated inputs and outputs prevent unwanted flow of electrical currents between instruments
and the multiplexer. These currents could damage the instruments or interfere with radio signals and
should therefore be avoided. Galvanically isolated inputs are required by the NMEA 0183 standard. As an
extra measure of protection, the MiniPlex-3 also has galvanically isolated outputs.
The host port or interface of the MiniPlex is also galvanically isolated in order to isolate the host from the
navigation network and protect it against potential damage caused by ground loops or voltage spikes.
Both NMEA outputs can drive up to four listeners each. Flexible routing options allow you to specify which
NMEA sentences are sent to these outputs. The outputs are also galvanically isolated. The NMEA 0183
standard does not require this but we added isolation because it makes the outputs more universal when
it comes to connecting them to different kinds of inputs (NMEA 0183/RS-422 or RS-232).
NMEA 2000
Some models in the MiniPlex-3 range (the ones
ending on ‘-N2K’) are equipped with an NMEA 2000
interface to connect to an NMEA 2000 backbone with
other navigation instruments. The MiniPlex-3 will
translate NMEA 2000 PGN’s (messages) into NMEA
0183 sentences and vice versa. This feature enables
a seamless integration between NMEA 0183 and
NMEA 2000 navigation devices. It also allows
navigation software, which usually only supports
NMEA 0183, to receive data from NMEA 2000
devices and to control NMEA 2000 autopilots. Figure
5 shows a typical setup, which makes the data from
the GPS/plotter available to the PC and a repeater.
Similarly, the data from the Depth, Wind and Log
instruments and the PC will be sent onto the NMEA
2000 backbone for use by the GPS/plotter and the
autopilot.
Feature Set
Besides the basic functionality of combining NMEA
sentences from multiple sources, the MiniPlex-3
offers a range of features like sentence filtering and
routing, input priority with automatic switchover,
testing of data integrity, NMEA 0183 conversions, Talker ID modification and SeaTalk®to NMEA
translation.
The MiniPlex-3 can be integrated seamlessly into an existing Raymarine SeaTalk network when SeaTalk
mode is enabled. This mode changes one NMEA input into a SeaTalk input. When connected to a
Figure 4
PCGPS
Depth
Wind
Log
MiniPlex-3
In1
In2
In3
In4
Out1
Out2
Host
Autopilot
Repeater
PC
Depth
Wind
Log
GPS/
Plotter
MiniPlex-3-N2K
In1
In2
In3
In4
Out1
Out2
Host
Autopilot
Repeater
NMEA 2000
NMEA 2000 Backbone
Figure 5

7
Raymarine SeaTalk network, the multiplexer translates SeaTalk data into NMEA sentences and combines
these with NMEA sentences that are received on the other inputs. Only one SeaTalk input is needed since
the SeaTalk bus connects all instruments together through one single cable.
SeaTalk to NMEA translation in the MiniPlex works one-way only: no NMEA sentences are converted into
SeaTalk, the multiplexer just listens on the SeaTalk bus.
All MiniPlex-3 models have the same features and number of NMEA inputs and outputs. The only
difference between each model is the type of host port. The following chapters describe the details of
each host port.

8
Host Port
The host port is the port that connects to a PC, laptop, smartphone, PDA, tablet or any device that is
connected to the multiplexer to receive the combined NMEA data for processing and display. The type of
host port differs for each type of multiplexer.
The host port is always bi-directional: it delivers the combined NMEA 0183/2000/SeaTalk data from the
multiplexer to the host and it also receives NMEA data from the host to be sent to the NMEA outputs of
the multiplexer. The host port is also used to configure the multiplexer and to update its firmware.
The following chapters describe each type of host port. The applicable type of multiplexer is listed
underneath the caption.
USB Port
(MiniPlex-3USB, MiniPlex-3USB-N2K)
The USB port is galvanically isolated from the multiplexer to prevent ground loops when connected to a
computer. Ground loops can result in excessive currents in ground connections, which could destroy the
multiplexer or the serial port of the connected computer.
Because of this galvanic isolation, a MiniPlex-3 with a USB port will not be powered from the USB bus
unlike older MiniPlex models. The MiniPlex-3 always requires a separate power supply to operate. The
USB port however does receive its power from the USB bus. A computer will therefore always show a
virtual COM port when the multiplexer is connected, with or without power supply.
The USB port supports flow control. Flow control is needed when waypoints and routes or other larger
amounts of data are sent from the computer to the multiplexer. The communication speed of the USB
interface is 10 to 100 times higher than an NMEA 0183 output. This causes the internal buffers in the
multiplexer to fill very rapidly, causing the multiplexer to drop sentences.
Flow control prevents this from happening. When the buffers in the multiplexer are almost filled up, the
multiplexer signals the computer to stop sending data. When the buffers are sufficiently emptied, the
multiplexer signals the computer to continue. This requires a special setting in your navigation software,
which is called “flow control” or “handshake”. This setting can mostly be found in the port settings of your
software.
Set the flow control to “Hardware” or “CTS/RTS”. Do not use “Xon/Xoff” flow control since this uses
special characters instead of a signal. These characters are not part of the NMEA standard and therefore
not supported by the multiplexer.

9
Driver Installation
To use a MiniPlex-3 with a USB port, a driver must be
installed. This driver creates a virtual COM port, which
can be opened by navigation software.
The CD contains drivers for Microsoft Windows
(Windows 2000, XP, Vista, 7, 8 and 10) and Apple’s
Mac OS X.
Windows 7 and up
When the MiniPlex is connected to the computer for
the first time, Windows will automatically download
the most recent drivers from the Windows Update
Service if an Internet connection is available. Without
Internet connection, these drivers must be installed
manually.
To install the drivers for the MiniPlex manually, open
the Control Panel, choose “System and Security” and
then “Device Manager”.
The Device Manager will show a “ShipModul MiniPlex-
3USB” listed under “Other Devices” as shown in Figure
6.
Right-click on the MiniPlex entry and choose “Update Driver Software...” from the menu that appears.
This will open the window as shown in Figure 7.
Choose “Browse my computer for driver
software”.
Figure 7
Figure 6

10
A new window opens (Figure 8) where
you must choose the location of the
driver. The driver is located in the
subfolder “\USB Driver\Windows” on the
MiniPlex Driver & Utility CD.
If you click on “Next”, Windows will
install the driver.
When Windows has successfully installed
the driver, the window as shown in
Figure 9 appears.
You can close this window.
Figure 8
Figure 9

11
The Device Manager will now list a “USB Serial Port”
under “Other Devices” (Figure 10). For this port to work,
a second driver needs to be installed.
Right-click on the USB Serial Port entry and choose
“Update Driver Software...” from the menu that
appears. This will open the window as shown in Figure
11.
Choose “Browse my computer for driver
software”.
Figure 11
Figure 10

12
A new window opens (Figure 12) where
you must choose the location of the
driver again. This time, the location is
already set and you can click on “Next”.
When Windows has successfully installed
the driver, the window as shown in
Figure 13 appears.
You can close this window.
The Device Manager will now list a “ShipModul MiniPlex
NMEA Multiplexer” under “Universal Serial Bus
controllers” and a “MiniPlex-3 Serial Port (COMx)” under
“Ports (COM & LPT)”.
Figure 12
Figure 13
Figure 14

13
Windows XP
When the multiplexer is connected to a USB port for the first time, Windows will detect new hardware
and prompts you for a driver. Insert the supplied CD into the drive and follow the instructions on your
screen. If you have an Internet connection, you can let Windows search the Internet for updated drivers.
Otherwise, when asked to automatically search for drivers, answer no and choose the option to tell
Windows where to find the driver. The driver can be found on the supplied CD, in de folder “\USB
Driver\Windows”
The installation on Windows is a two-step process. First, the driver for the multiplexer will be installed.
Next, Windows will detect a USB Serial device and will install a second driver. On Windows XP systems,
there can be a delay of up to 10 seconds between the installation of both drivers, which sometimes leads
to the wrong conclusion that the installation is complete after the first driver is installed. On Windows
Vista and Windows 2000 systems, there is only very little delay.
When the installation is complete, a new virtual COM port will be created.
If necessary, the number of this COM port can be changed in the Windows Device Manager. Click on the
‘+’ sign next to the entry marked as “Ports (COM & LPT)”. This will expand the entry to list all available
COM ports on your computer. The port for the multiplexer is listed as “MiniPlex Serial Port (COMx)” where
“COMx” is the name of the newly created serial port.
To change this port number, double click on the “MiniPlex-3 Serial Port (COMx)” entry to open the
property page for this port. Next, select the “Port Settings” tab and click on the “Advanced…” button. In
the appearing window the assigned port number can be changed. Do not change any other setting in this
window.
It is possible to select a port number that is already present on the computer, like COM1. The original
COM1 port will then be disabled as long as the multiplexer is connected to the computer. This feature
allows the port number to be set in a low range from COM1 to COM4, to accommodate software that only
allows COM1 to COM4 to be selected.
More than one multiplexer can be connected at the same time. Every new unit will create a new virtual
COM port. Once created, the COM port will always be assigned to the same multiplexer regardless of the
USB port being used.
Windows allows a maximum of 256 COM ports. However not all software may be able to select COM ports
numbered above COM9.
When installing updated drivers, uninstall the original drivers first with the “Add/Remove Programs” icon
in the Control Panel or use the “Update Driver”button on the Driver page of the “MiniPlex Serial Port”
property-page.
Mac OS X
The OS X driver is available as a disk image file (.dmg) and can be found on the supplied CD in the “USB
Driver” folder. Run the installer by double clicking on the icon. Follow the instructions on the screen.
When the installation is complete, plug in the USB cable of the MiniPlex. The MiniPlex will show up in the
ports list of your navigation software as MiniPlex-xxxxxxxx where the xx’s represent the serial number of
the MiniPlex.

14
Network Interface
(MiniPlex-3E, MiniPlex-3E-N2K)
A network interface connects the multiplexer directly to a network with possibly more than one device.
There can be more than one multiplexer connected to a network and/or more than one device that needs
to communicate with a multiplexer.
Network Basics
In order to understand how a networked multiplexer works and how to connect to it, it is necessary to
know a little bit about IP addresses, port numbers and protocols.
IP Address
Every device on a network needs a unique number to be able to identify that device. This allows us to
send a message to one single device on a network. These unique numbers are called MAC addresses and
every device in the world that is connected to a network has a unique MAC address. The MAC address of
a MiniPlex-3E or -2Wi multiplexer is printed on the serial number label and looks like
00-20-4A-E4-28-58
These addresses are a bit cryptic and not easy to work with. Therefore a mechanism is used to assign a
more easy to read number to a device, called an IP address. An IP address consists of four numbers
grouped together, separated by dots. Each number can range from 0 to 255. An IP address looks like
this:
192.168.1.45
Assigning an IP address to a device could be compared to sticking a coloured label to your house. Now
the postman only needs to remember the colour of your label instead of your complete address. Of
course, someone needs to manage a list that matches the colour to your address in order to prevent two
houses of receiving the same coloured label. Networks and network devices have mechanisms built in
that take care of this so we don’t have to worry about it (it’s called ARP or Address Resolution Protocol).
Netmask
Another tricky bit of networking is a netmask. A netmask basically determines which part of an IP
address is the network address and which part is the device address. In its most basic form, a netmask
consists of four numbers, similar to an IP address, that are either 255 or 0. And the 255’s always come
first. A device always has an IP address AND a netmask, for instance:
192.168.1.45 and 255.255.255.0
This combination of IP address and netmask tells us that the first three numbers of the IP address are
the network address (192.168.1) and the fourth (45) is the device’s address. It also means that this
particular combination limits the number of devices on this network to 254 (0 and 255 are reserved).
A network address allows us to send a single message to all devices on the network, instead of sending it
to one single device. This is called a broadcast (see below). In this example, the broadcast address is
192.168.1.255. The last number here is 255, which means that it targets all devices on the network.
If we have an IP/netmask combination of 192.168.1.45/255.255.0.0, it means the network address is
192.168 and the device’s address 1.45, that there are 65534 possible devices (0.0 and 255.254 are
reserved) and that the broadcast address is 192.168.255.255.
If you’re completely lost at this point, don’t worry. Just remember two things:
•All devices on a single network must have the same netmask
•All devices on a single network must have the same network address
So when the netmask for example is 255.255.255.0, the first three numbers of the IP addresses must be
the same.
Port Number
A port number can be seen as a sub address within one single device. When a message is sent over the
network, it always contains the IP address of the sender, the IP address of the receiver and a port
number. This port number is just a logical number that determines the type of data in the message.
Web servers for instance, always listen to messages that have port number 80. If you start your web
browser and enter the name of a web site, the request to show the contents of a page is sent to a web
server using port number 80. Similarly, your mail program always uses port number 110 to retrieve mail
from a mail server and port number 25 to send mail to a mail server.

15
The use of different port numbers allows us to use the same physical device on a network for different
services.
Port numbers are not chosen arbitrarily, they are standardized and controlled by an organization called
IANA.
Our multiplexers all use port number 10110, which is a registered port for NMEA data.
Protocols
Two transport protocols are available for sending data over the network: UDP and TCP. UDP can be used
in two different modes: Broadcast and Directed.
UDP Broadcast
NMEA sentences are broadcast on the network using UDP messages. Every device on the network will
receive these messages. At the same time, any device on the network can send data to the multiplexer,
either to its IP address (directed) or as a broadcast. UDP Broadcast has the following properties:
•Every device on the network will receive NMEA data from the multiplexer.
•Every device on the network can send NMEA data to the multiplexer.
•Other MiniPlex-3E/2Wi’s on the same network will also receive each other’s data. It is therefore
possible to send NMEA data over the network from NMEA device to another. Care should be taken to
prevent buffer overflows by selectively routing the desired NMEA data to an NMEA output at the
receiving end and blocking unwanted NMEA data.
•Routers do not pass UDP Broadcasts from one network to another so this mode can only be used on
one network.
•Delivery of NMEA data is not guaranteed, messages can be lost.
•Wi-Fi routers often assign a low priority to UDP broadcasts, resulting in dropped messages. Typically
up to 5% of the messages gets lost.
UDP Directed
With directed UDP data is sent to a specific IP address. The advantage is that it travels across routers and
networks and can therefore also be used to send NMEA data over the Internet. Any device on the
network can send data to the multiplexer either to its IP address (directed) or as a broadcast. Directed
UDP has the following properties:
•Travels across routers/networks and the Internet.
•Higher change of delivery than UDP broadcast.
•Every computer on the network can send NMEA data to the multiplexer.
•Only one computer can receive NMEA data from the multiplexer.
•Delivery of NMEA data is not guaranteed, messages can be lost.
TCP
When using TCP, a device sets up an exclusive connection with the MiniPlex. The TCP protocol is reliable,
which means that when data gets lost on the way from one device to another, it is automatically
retransmitted. Both the MiniPlex-3E and the MiniPlex-3Wi are limited to one TCP connection at a time.
TCP has the following properties:
•Travels across routers/networks and the Internet.
•Only one computer or other device may communicate with the multiplexer.
•Reliable connection. Lost messages are automatically retransmitted.
Although TCP might seem the best option from the above, it is favourable to use UDP. Compared with
TCP, UDP will minimize network bandwidth. To send periodically updated sensor data, it is usually more
appropriate to NOT use a guaranteed-delivery protocol like TCP. In navigation applications, the best thing
to do in the rare event that a message doesn't get through is to simply wait for the next message. The
TCP protocol forces retries which increase network traffic unnecessarily.
UDP resembles NMEA the most because NMEA is also a message based broadcast protocol without any
acknowledgements or retries.
Assigning IP addresses
When devices are connected to a network, they all must have a unique IP address and a matching
netmask. One way of achieving this is to set the IP address and netmask of each device manually. The
other way is to let a DHCP server take care of this.
DHCP is an acronym for Dynamic Host Configuration Protocol and it is a mechanism to automatically
assign IP addresses to devices (hosts) on a network. A DHCP server on a network will respond to
requests from DHCP clients to obtain an IP address.

16
In a typical network environment, a router acts as a DHCP server while other devices such as computers,
laptops, tablets and smartphones are DHCP clients, receiving IP addresses from the DHCP server. This
ensures that you can connect these devices to the network without worrying about IP addresses,
netmasks and gateways - al of this is taken care of by the DHCP server.
The MiniPlex-3Wi acts as a WiFi access point with a DHCP server built-in. When a device joins its WiFi
network, it will automatically receive an IP/netmask from the MiniPlex-3Wi. The only thing you have to do
is to enter the fixed IP address of the MiniPlex-3Wi (10.0.0.1) in your navigation software.
The MiniPlex-3E is completely different in this respect. It has a DHCP client and thus relies on a DHCP
server already present on the network to obtain an IP/netmask automatically. If no DHCP server is
present, you have to manually assign an IP/netmask. This is the case for instance, if your “network” is
just the MiniPlex-3E and a computer. Obviously you will need to assign a manual IP address and netmask
to your computer too in this case.
Auto-IP
When DHCP request remains unanswered, a device assigns itself an IP address in the range of
169.254.0.0 to 169.254.255.254 with netmask 255.255.0.0. This is called an Auto-IP address. Although
two devices with an Auto-IP address on the same network can perfectly communicate with each other,
this is not a desired situation because these addresses are assigned totally at random. So every time a
devices powers up, the address changes within the Auto-IP range and you’ll never be sure of its IP
address. Also, the time it takes for a device to auto-assign varies wildly from a few seconds to over a
minute.
MiniPlex-3E Network Setup
When you are going to use a MiniPlex-3E, it is important to know whether your network has a DHCP
server. If a DHCP server is present on the network, you don’t need to manually assign a fixed IP address
to the MiniPlex-3E if the following conditions are met:
•The DHCP server always assigns the same IP address to the same MAC address
•The DHCP pool of free addresses will never be exhausted
This ensures that the MiniPlex-3E will always get the same IP address. The best practice however is to
assign a fixed IP and netmask to the MiniPlex-3E.
In order to find the MiniPlex-3E on the network, first select TCP with the Port selector in the “MiniPlex
Connection” box. After this, the Tools menu will show a “MiniPlex-3E” sub-menu. From this sub-menu,
select “Search…”
This will bring up a window showing the MiniPlex-3E’s
found on the network (Figure 15). In this case there’s
only one and its IP address appears to be 192.168.1.95.
The cryptic number in brackets is the MAC address of the
multiplexer, which is also printed on the serial number
label. If you select this entry and click OK (or double-click
on the entry), the window closes and the IP address is
transferred to the Host field in the “MiniPlex Connection”
box. At this point you can click on the Connect button to
open a connection with the multiplexer and the MPX-
Config-3 window should show some NMEA sentences in
the NMEA viewer.
If the listed address is an Auto-IP address in the
169.254.x.x range, click on the “Change IP Address”
button to assign a sensible IP address to the MiniPlex.
When done, the window will show the MiniPlex with the
newly assigned address and it can be selected for normal
use. You can use the “Factory Reset” button to restore
the network settings to its factory defaults if necessary
(DHCP and UDP broadcast).
If you’re happy with the DHCP assigned IP address and the default TCP mode, there is no further network
configuration required and you can proceed with the normal multiplexer configuration as outlined in
chapter “MPX-Config” on page 27.
To change any of the network settings, make sure the IP address of the multiplexer is in the Host field in
the “MiniPlex Connection” box and select menu Tools !MiniPlex-3E !Network Setup… This will open the
“MiniPlex Network Settings” as shown in Figure 16.
Figure 15

17
These are the factory default settings.
The IP address shown here is 0.0.0.0,
which means the multiplexer is set to
DHCP. This address is different from
what you have entered in the Host
address field on the main window
because that is the address that the
MiniPlex received from the DHCP
server.
You can now enter the desired IP
address and a netmask that matches
your network. The Gateway IP can be
left to 0.0.0.0 if you are not going to
set the multiplexer to UDP Directed.
The example in Figure 17 shows fixed
IP settings.
If you set the multiplexer to UDP
Directed, you must enter a destination
IP address in the Destination field. If
this IP address is not on the same
network as the multiplexer, you must
also enter the address of your network
gateway in the Gateway IP field.
Please note that when UDP Directed is
enabled, you will not receive any NMEA
data from the multiplexer anymore
when the IP address of your computer
is different from the Destination IP. The network settings however can always be changed regardless of
this setting.
If you click on the OK button to activate the settings, a progress bar will appear because the network
interface must be restarted and this takes approx. 7 seconds. The new IP address and protocol will
appear automatically in the Host and Port controls on the main window of MPX-Config-3 when the
process is completed.
If you need to change the network settings back to DHCP, set the IP Address field to 0.0.0.0 and click
OK.
In some cases, the settings of the multiplexer cannot be verified after change, for instance because the
IP address is changed from a fixed address to DHCP (0.0.0.0) or when an IP address is entered which is
not on your network. In this case, a warning will appear.
Search
The search function (menu Tools !MiniPlex-3E !Search…) will almost always find any MiniPlex-3E on
the network, even if it has been configured with the wrong IP/Netmask combination for the network it is
connected to. In rare cases MiniPlex-3E cannot be found.
See the paragraph “Network Recovery” below how to deal
with this situation.
The search result window (Figure 18) has two buttons
that allow you to restore the network settings to the
factory default values and to change the current IP
address in case it is outside your network. In that case
the normal network setup cannot be used.
Figure 16
Figure 17
Figure 18

18
Network Recovery
In rare cases a MiniPlex-3E might not show up in the search
results window due to a possible misconfiguration in the Network
Settings. This might happen when duplicate IP addresses exist on
the network or the multiplexer has an illegal IP address. To
recover from such a situation, a new IP address can be assigned
with menu option “Tools !MiniPlex-3E !Assign IP”.
In the “Assign IP Address” dialog (Figure 19), enter the MAC
address of the multiplexer. This MAC address can be found on the
label on the topside of the multiplexer, below the serial number.
Enter the MAC address with the fields separated by dashes as
shown. Then enter a valid IP address and click on OK. A progress
bar will appear during the update process, which will take approximately 10 seconds. After that, the
multiplexer can be reached again through the normal “Network Settings”dialog.
Figure 19

19
NMEA 0183 Ports
The NMEA 0183 ports are the inputs/listener ports and outputs/talker ports on the MiniPlex-3, which
connect to NMEA 0183 ports on navigation instruments, chart plotters etc. There are many
interpretations and variations of NMEA 0183 ports so we’ll explain a few things first.
NMEA 0183 Signals
Although the NMEA 0183 standard specifies the signal names, voltage levels and connection methods
very clearly, the reality is far from this ideal world.
The most important property of an NMEA 0183 port is that the connections or wires are labelled A and B
and that it uses a differential signalling scheme. This means that data is transmitted on both wires, but in
“opposite direction”. Both wires are driven between 5V and 0V and opposite of each other: when wire A is
at 5V, wire B is at 0V and when wire A is at 0V, wire B is at 5V. The advantage of this signalling scheme
is that it is very insensitive to electrical interference.
NMEA A and B are often labelled as NMEA + and - respectively. When connecting devices, simply connect
NMEA A to NMEA A or NMEA + and NMEA B to NMEA B or NMEA -.
Some devices even have NMEA + and NMEA – the other way around. It is perfectly safe to swap the
wires if no signal is received when connected to an NMEA 0183 port of the MiniPlex-3.
Things get complicated when manufacturers don’t follow the NMEA 0183 standard, which is very often
the case. Many devices have an NMEA 0183 interface, which is electrically speaking an RS-232 interface.
The only resemblance with the NMEA 0183 standard is the format of the data transmitted. Electrically,
they are an entirely different world. The used signal names differ wildly and often lead to confusion.
When a device has a NMEA input with connections “Data In” and “Data Return” it is often not clear
whether this input is galvanically isolated or if “Data Return” is simply another name for “Signal ground”.
Instead of being fully compatible with the NMEA 0183 standard, many devices use a single-ended
signalling scheme where data is transmitted on one a single wire while the power ground provides the
return path. Single ended devices often have connection names like TX and Gnd (transmit and ground)
on the NMEA output and RX and Gnd (receive and ground) on the NMEA input. Also used are Data Out,
Data In and Signal Ground. Mix these with standard NMEA connections and confusion is imminent!
The MiniPlex-3 Series multiplexers takes away the confusion by offering galvanically isolated NMEA inputs
and outputs. Because of this isolation, a ground reference no longer exists: both the A and B signals of
an NMEA port are completely “floating”. This means that you don’t have to think about the nature of an
input or output of the device you want to connect to multiplexer. Any NMEA output of a device can be
connected to an NMEA input of the multiplexer while an NMEA output of the multiplexer can be connected
to any type of input of your device or instrument.
NMEA 0183 Inputs
The MiniPlex-3 has four NMEA inputs called In1 to In4. Each input should be connected to one output
only. These inputs are galvanically isolated from the multiplexer, as specified by the NMEA 0183
standard.
The default communication speed of the NMEA 0183 inputs is 4800 Baud (NMEA standard) and it can be
set to any value from 4800 to 57600 Baud using MPX-Config-3. Set the speed of an input to 38400 Baud
if it will be connected to an AIS receiver or transponder.
Connect the A and B terminals of the NMEA input on the multiplexer to the A and B terminals of the
NMEA 0183 output on the navigation device as shown in Figure 20 on the left. These terminals may also
be labelled as Data+/Data-, TX+/TX-, Out+/Out– or ve+/ve-.
Some navigation devices have single ended outputs with only one data terminal. Connect this terminal to
the A terminal of the multiplexer input, and connect the ground of the navigation device to the B terminal
of the multiplexer input as shown on the right in Figure 20. The navigation device’s data ground is often
combined with its power supply ground. In that case, connect the power ground of the navigation device
to the B terminal of the multiplexer input.

20
Figure 20
NMEA 0183 Outputs
The MiniPlex has two NMEA 0183 outputs called Out1 and Out2. Each output is capable of driving up to
four NMEA 0183 inputs.
The default communication speed of NMEA Out1 is set to 4800 Baud while NMEA Out2 is set to 38400
Baud. This speed can be set to any value from 4800 to 115200 Baud using MPX-Config-3.
Connect the A and B terminals of the NMEA output on the multiplexer to the A and B terminals of the
input(s) on the instrument(s). These terminals may also be labelled as Data+/Data-, RX+/RX-, In+/In–
or ve+/ve-.
Some instruments may have single ended inputs, with only one data terminal. Connect this terminal to
the A terminal of the multiplexer output, and connect the B terminal of the multiplexer output to the
ground terminal of the instrument. Figure 21 shows several examples of differential and single ended
connections and combinations of both.
Figure 21
The shield terminals on the multiplexer (Shld) can be connected to the shield of the cable if available.
This should always be done on one end of the cable only, preferably on the end that is connected to an
NMEA output.
Multiplexer
In A
In B
Instrument
Out A/+
Out B/-
Differential
Multiplexer
In A
In B
Instrument
TX/Out
Ground
Single ended
Multiple differential and
single ended listeners
Instrument
In A/+
In B/-
Multiplexer
Out A
Out B
Differential
Instrument
RX/In
Ground
Single ended
Multiplexer
Out A
Out B
Instrument
In A/+
In B/-
Multiplexer
Out A
Out B
Instrument
In A/+
In B/-
Instrument
RX/In
Ground