Actisense | NMEA 0183 | User manual | Actisense NMEA 0183 User manual

NMEA Data Multiplexer
For all variants:
Install User Manual
Issue 1.07
Multiple talker interface for use with the NMEA 0183 standard. Serial data
networking of marine electronic devices / instruments.
RS232 & USB 1.1 & 2.0 PC interfaces to the NMEA 0183 standard.
Actisense ISO-Drive technology for a fully isolated serial data system.
Intelligent NMEA filtering on all inputs allows smart removal of NMEA data.
Re-configurable to work as an NDC-4-ASW Autoswitch to allow the automatic
switching between up to 4 NMEA inputs.
NMEA Data Multiplexer - NDC-4
Important Notices
General Features
Technical Features
Software Updates
Connecting devices together
Connecting to NMEA Devices
Other Connections
The Basics
The NMEA Signals
The Different NMEA Standards
OPTO Inputs
ISO-Drive Outputs
Connecting to the Battery Supply
Connecting to a Personal Computer
USB Driver Installation
USB Configuration
Actisense PC Software suites
Configuration of AIS
The NDC-4-ASW Autoswitch
Troubleshooting Guide
Order Codes
Returns Procedure
Company Information 19
Installation Guide
Windows 7 and Windows Vista
Windows XP and Windows NT/2000
Locate and Change the Port Number
Installing Actisense PC software
Uninstalling Actisense PC software
Setting up the Hardware for AIS
Setting the NDC-4 as an Autoswitch
Diagnostic LED
© 2011 Active Research Limited
Page 3
Important Notices
Actisense and the Actisense logo are registered
trademarks of Active Research Limited. All rights are
reserved. The contents of this manual may not be
transferred or copied without the express written
permission of Active Research Limited. All other
trademarks are the property of their respective owners.
Actisense recognises that instructions are often skipped,
so we have aimed to write this document in an informative,
yet direct manner that will aid the user. We have tried to
cover all the points a typical user may need to know.
Please read all sections before installing and using the
Actisense NMEA Data Multiplexer product and any
related software programs.
The Actisense NMEA Data Multiplexer / Combiner /
Autoswitch (NDC-4) is intended for use in a marine
environment, primarily for below deck use. If the unit is to
be used in a more severe environment, such use may be
considered misuse under the seller’s guarantee.
The Actisense NDC-4 has been certified to comply with
the European directive for Electromagnetic Compatibility
(EN60945), and is appropriately CE marked. Operation of
the unit should be in conjunction with appropriate CE
approved shielded connectors and cabling used in
accordance with the CE directive EN60945. Any EMC
related issues should be reported to Active Research
Limited immediately to allow the company to rectify or
resolve EMC related problems in accordance with its
obligations under EN60945.
If the unit is connected such that compliance failure occurs
beyond the company’s control, the company shall not be
held responsible for compliance failure until suitable EMC
guidelines for connection are seen to have been taken.
The products and specifications described in this guide
may be changed without prior notice. To obtain the latest
information visit
Active Research Limited will not be liable for infringement
of copyright, industrial property right, or other rights of a
third party caused by the use of information or drawings
described in this manual.
The NGW-1-USB must be used in accordance with the
manufacturers instructions. Active Research Limited will
not be held responsible for any damage or injury, direct or
otherwise, as a result of failure to adhere to these
The NDC-4 does not validate the NMEA data it receives in
any way. Neither the NMEA sentence checksum, nor the
data contained within the NMEA sentence is validated.
Therefore, the electronic device(s) supplying the NDC-4
with NMEA data retain(s) the sole responsibility for the
NMEA data’s validity.
© 2011 Active Research Limited
The Actisense NDC product range developed out of the
requirement to solve two fundamental problems with the
existing marine industry NMEA 0183 communications
In theory, the NMEA 0183 standard allows any suitably
designed marine electronic device to share its gathered
information with any other device on a vessel.
Unfortunately, there is one very large drawback with this
standard - only one device on a connected network can
actually send data (a single talker), with multiple devices
(determined by the current limit of the sending unit)
listening to that data (multiple listeners).
If the vessel owner has an instrument that ideally requires
the data output of two or more devices, for example a
chart-plotter, then the owner has no alternative but to
settle on connecting only the most important device (that
which supplies the most used information), normally that is
the GPS unit. All other devices cannot be used.
What happens if the owner prefers the vessels gyro
compass heading output to that of the GPS, or requires
that the current depth be displayed on the plotted chart to
help avoid the possible case of running the vessel aground
on a shifting sand bank? The NMEA 0183 standard cannot
supply an answer to those questions as it can handle only
one transmitting device.
These two elementary problems can be solved simply and
easily with the Actisense NMEA Data Multiplexer’s very
flexible design approach.
Alternately, if the vessel has two or more identical NMEA
devices (e.g. GPS’s or depth sounders) the system
solution could be to use the NDC-4 as an NMEA Autoswitch
to select the highest priority source.
Full information on the complete Actisense product range
can be found on the Actisense website (www.actisense.
Page 4
NMEA Data Multiplexer - NDC-4
General Features
million instructions per second.
4/5 Opto-isolated Input Ports
The NMEA 0183 inputs are galvanically opto-isolated
differential inputs, protecting against common mode
voltage differences of up to 2500v. Fully compliant with the
NMEA 0183 standard specification and compatible with
RS232, RS422 and RS485 signal levels. The typical
operating voltage is 2.0v to 15.0v and can withstand +/35v continuously and +/- 40v transients. Compatible with
both differential and single ended inputs.
Each Opto-isolated input port has a priority level. This
defaults to the logical order matching the port numbers,
i.e. port 1 has the highest priority and port 4 has the lowest.
When the USB cable is not plugged in (or not powered),
OPTO IN 0 can be used as a fifth fully compliant NMEA
0183 data input, appearing last in the priority list.
2 ISO-Drive Output Ports
These outputs combine the input data into standard NMEA
outputs with independent Baud rate selection options,
defaulting to 4800 (OUT 1) and 38400 (OUT 0). If the
combined Baud rate of all NMEA inputs exceed the output
Baud rate, it is possible that the combined data could
exceed the data carrying capacity of the NMEA output
channel. The multiplexer contains special software to
ensure that when the output channel is overloaded, new
data of the same type as older data, still in the buffer, will
overwrite the older sentence.
A PC RS232 or USB Bidirectional Port
The RS232 compatible Port 0 (OPTO IN 0 plus ISO OUT
0) and the USB interface ensures that any device (or PC),
that has an RS232 or USB port, receives all the input
NMEA data, and can add its own NMEA data to ISO OUT
1. This allows for the possibility of a “virtual cockpit” of
instruments displaying all available data in any manner the
user requires (available from a number of manufacturers).
These connections also allow the unit to be updated via
the freely available ActiPatch flash upgrade software that
will be made available on the Actisense website when the
NDC-4 firmware has been enhanced.
1. When the USB cable is plugged in and powered up, it
disables OPTO IN 0 on the NDC-4.
2. NDC-4 variants that don’t come with a USB cable can
be upgraded by purchasing a USB Upgrade Kit.
Technical Features
Flash ROM technology that supports automatic
programming for quick and easy updates, 100,000+ erase
cycles and a 10 year Data Retention provides carefree
user configuration.
On-chip memory store allows buffering of short-term
NMEA data, allowing the unit to smooth short-term peaks
in the NMEA data flow.
A diagnostic LED indicates the operation mode of the
NDC-4, if any faults have been detected, or the peak load
currently on any one of the NMEA inputs.
High-speed 32-bit ARM processor capable of up to 40
© 2011 Active Research Limited
ISO-Drive output technology unique to Actisense,
protects against common mode voltage differences of up
to 1500v. The output automatically changes between
differential and single ended drive depending upon the
type of instrument it is connected to. Fully compliant with
the NMEA 0183 standard specification and compatible
with RS232, RS422 and RS485 signal levels.
Wide battery input voltage range to offer maximum
compatibility, the NMEA 0183 NDC-4 can operate from a
battery supply anywhere between 8 and 35 volts.
USB powered option is available when the battery source
is not present. When the main battery is present, the USB
power drain is minimal. WARNING: The USB and battery
grounds are not isolated, see “USB Warning” on page 9.
Very tough Polycarbonate case is certified to IP66 (Protection against heavy seas, or powerful jets of water),
the addition of non-acid based marine sealant to the
gasket can increase this to IP67 (Protection against
immersion). Being Polycarbonate, it is also incredibly
strong, offering a wide temperature range and superior
protection to the electronics inside.
Robust Nylon grommets are certified to IP68 (Protection
against complete, continuous submersion in water).
Note: To achieve this level of water integrity all glands
must be occupied by round-section cables of between
4.5mm and 10 mm or be replaced by blanking plugs.
Large range of possible cable diameters of between
4.5 mm and 10 mm, single or multi-pair wire types can be
easily accepted.
Software Updates
The NDC’s built-in firmware is held in ‘flash’ memory,
allowing quick and easy upgrades using a simple Microsoft
Windows™ NT/2000/XP/Vista/7 user interface program
(ActiPatch) running on a connected PC.
It is our policy to provide these updates free on the
Actisense website ( This upgrade
can be performed with the unit completely in-situ, via a PC
connected to either Port 0 (OPTO IN 0 and ISO OUT 0) or
the USB port.
Page 5
Connecting devices together
The Basics
NMEA data is transmitted from an information source such
as GPS, depth sounder, gyro compass etc. These data
sending devices are called “Talkers”.
Equipment receiving this information such as a chartplotter, radar or NMEA display is called a “Listener”.
Unfortunately, only one Talker can be connected on to a
single NMEA 0183 system at any one time. Two or more
Talkers are simply not possible because they are not
synchronised to each other, and will attempt to ‘talk’ at the
same time (over each other), resulting in corruption of the
NMEA data, and potentially in disaster if valuable data
such as navigation information is lost or corrupted so that
it is incorrect and/or misleading.
The Different NMEA Standards
The NMEA 0183 specification has slowly evolved over the
years, so connecting one device to another is not always a
straightforward matter. The earlier versions of NMEA 0183
(before v2.0, as detailed above), used slightly different
connection methods and signal levels: the instruments
had just one “NMEA” data line (‘Tx’ or ‘Out’), and used the
ground as the other line - similar to the way a computer
serial port works. This connection method is referred to as
“single ended” instead of the “differential” method used by
NMEA 0183 v2.0 devices.
The data format is largely the same between both systems,
with v2.0 adding some extra sentence strings, and
removing older (redundant) sentence strings from the
specification. The situation is further complicated, as many
manufacturers still use the old (“single ended”) method of
connection because it is cheaper to implement.
Actisense produces a full range of products to solve all
NMEA interfacing requirements.
So how can an older type NMEA device be connected to a
newer type device?
Please visit the Actisense website (www.actisense.
com) for full details on these and other Actisense
interfacing, Depth sounding and NMEA 2000 products.
Care is needed – it is possible to damage or overload the
output of a newer differential device if it is incorrectly
connected to an older device. This is because the older
devices used ground as the return, whereas the newer
devices actually drive the NMEA ‘-/B’ line between 5v and
0v. Thus, connecting this output to ground will result in
high currents being drawn by the driver instrument,
resulting in potential overheating and damage to the driver
The NMEA Signals
The NMEA 0183 system v2.0 and later uses a ”differential”
signalling scheme, whereby two wires are used to transmit
the NMEA data. These connections will be labelled as
either NMEA ‘A’ and ‘B’ or NMEA ’+’ and ‘-’ respectively,
depending on the instrument and manufacturer.
When connecting between different manufacturers, there
can be some confusion, but it is simple and easy to
remember: NMEA ‘A’ connects to NMEA ‘+’ and NMEA ‘B’
connects to NMEA ‘-’.
However, the new Actisense ISO-Drive technology allows
the user not to worry about this potentially damaging incompatibility. Instead, an ISO-Drive output can be
connected to an old type single-ended system, by
connecting the NMEA ‘+/A’ output from the ISO-Drive to
the single-ended NMEA ‘Rx’ or “In” input of the device.
Connect the NMEA ‘-/B’ output of the ISO-Drive to the
ground of the single-ended device. This provides the
required data signal return current path.
To connect an old type single-ended device to an OPTO
IN input, connect the NMEA ‘Tx’ or ‘Out’ output from the
single-ended driver to the OPTO IN ‘+/A’ input of the NDC4. Connect the ground line of the single-ended output
device to the OPTO IN ‘-/B’ input of the NDC-4. This
provides the data signal return current path. If the NMEA
‘-/B’ input is left floating, then data corruption / errors may
Please refer to “Connecting to NMEA devices” on page
8 for examples of these connection methods.
© 2011 Active Research Limited
Page 6
NMEA Data Multiplexer - NDC-4
Figure 1 – All external connections
The NMEA Data Multiplexer (NDC) has screw-terminal “Phoenix” type external connections for: 1. Five Opto-isolated Inputs.
All inputs are of the differential opto-isolated type and use
the unique Actisense low current drain circuitry (2mA @
2.0v) to conform in full with the NMEA 0183 marine
electronic device network communication standard, and
are flexible enough to interface to most fully and partially
compliant devices.
2. Two ISO-Drive Outputs.
The ISO-Drive outputs comprise of two connections: ‘+/A’
and ‘-/B‘ and conform in full to the NMEA 0183 standard.
3. RS232 Compatible Input/Output Option.
The ISO OUT 0 and OPTO IN 0 connections can be used
as a bidirectional RS232 compatible port and is designed
for direct connection to a Personal Computer (PC) or other
marine device capable of interfacing to a standard RS232
When a USB cable is powered and plugged into the NDC4, this port switches to output only - i.e. the RS232 input
(OPTO IN 0) no longer operates.
© 2011 Active Research Limited
4. A USB Input/Output (USB Variants Only).
The USB connector is designed for direct connection to a
PC’s USB port. Once the USB cable is powered and
plugged into the NDC-4, Port 0 switches to an output only
mode - this allows the USB port to take over bidirectional
control of the NDC-4.
5. Battery Supply Input.
Standard battery power connections (8 to 35v).
1. To complete the NMEA 0183 standard all device
interconnection NMEA cables used should meet the twoconductor,
specification. The shield connection of these wires should
be connected at the instrument end only to prevent ground
2. Refer to “Specifications” on page 19 for the full details
on input/output specifications.
Page 7
Connecting to NMEA Devices
Talker 4
Listener A G
Talker 3
Talker 2
Talker 1
Listener C B
Listener B
Personal Rx
Computer G
Figure 2 – NMEA 0183 connections
OPTO Inputs
ISO-Drive Outputs
The differential opto-isolated inputs are designed to handle
a variety of NMEA 0183 device output specifications.
Please determine (from device manufacturer’s information)
if the device(s) required to be connected to the NDC-4
conforms in full to the NMEA 0183 network communication
standard. If it does not, the flexible NDC-4 inputs should
still be capable of interfacing with the device, though this is
not guaranteed.
The ISO-Drive outputs are capable of driving up to 10
NMEA 0183 fully compliant listening devices, or a mixture
of NMEA 0183 devices and a Personal Computer (PC)
communication port. However, if you wish to maintain
isolation between all devices, then only one listening
device should be connected to an ISO-Drive output.
The diagram above shows a typical installation with both
fully compliant NMEA devices with differential inputs/
outputs, and non-differential output devices.
Note: All NDC-4 inputs are identical and the connections
shown are examples that can be used on every input port.
NMEA Talker Devices 1 and 2: These devices conform in
full to the NMEA 0183 standard. Talker 1 shares the same
connection ID’s as the NDC-4, so connection is a simple
matter of matching the ID’s. Connect ‘+’ to ‘+/A’ and ‘-’ to
‘-/B’ or ‘A‘ to ‘+/A‘ and ‘B’ to ‘-/B’ (refer to figure 2).
NMEA Talker Devices 3 and 4: These devices do not
conform completely to the NMEA 0183 standard. However,
by connecting ‘+‘ to ‘+/A‘ or ‘Data/Signal’ to ‘+/A‘ and ‘G/
Ground’ to ‘-/B’ the NDC-4 should receive the NMEA data
© 2011 Active Research Limited
NMEA Listener Device’s B and C: These devices
conform in full to the NMEA 0183 standard and their
connection ID’s match that of the NDC-4.
Personal Computer: Whilst the OPTO IN 0 and ISODrive 0 provide a bidirectional RS232 compatible port for
connection to a PC, the ISO-Drive 1 output is also capable
of being read by a PC’s RS232 port. Simply connect ‘+/A’
to ‘Rx’ and ’-/B’ to ‘G/Ground’ on a standard D-type
connector. See “Figure 26 - DB9 Connection” on page 8 of the “Full user manual” available on the CD and from for a diagram of this wiring
NMEA Listener Device A: This device does not conform
in full to the NMEA 0183 standard. However, by connecting
‘+/A‘ to ‘+‘ or ‘Data/Signal’ and ‘-/B’ to ‘G/Ground’ the
device should be able to receive the NMEA data correctly,
though this is not guaranteed.
Note: Wire colours are for guidance only.
Page 8
NMEA Data Multiplexer - NDC-4
Other Connections
+ -
Tx Rx G
Battery /
Power Supply
PC or
PC or
Figure 3 – RS232, USB and Battery connections
USB Warning!
USB power and battery power are NOT
isolated from each other. Consult a qualified installer to
ensure there is no ground loop hazard when connecting
both. Disconnecting a single battery lead or turning off
the supply does NOT prevent this ground loop hazard.
Ground loop damage is NOT covered by the guarantee.
For installs where the NDC-4 must still operate when
the PC is switched off, full PC isolation can be
maintained by using Port 0 (‘OPTO IN 0’ and ‘ISO OUT
0’) as the PC connection.
Connecting to the Battery Supply
The NDC-4 can be powered either by the USB connection
or through an external power source. If both power sources
are available, the current drawn from the USB supply will
be reduced to a trickle. If the external power source is
removed, the USB power will seamlessly take over, without
loss of data.
If the NDC-4 is powered from an external power source,
like a battery, it should be wired to the vessel’s battery
supply in the most direct manner possible, to minimize
interference from other electronic devices. The cable used
should be of sufficient gauge to handle the power
requirements of the NDC-4 (refer to ”Specifications” on
page 19).
Connecting to a Personal Computer
The USB port can be used to connect a PC to the NMEA
0183 system. A USB cable is available in the form of an
upgrade kit for variants that do not come with a cable. The
part number will include “USB” if a cable is provided with
that variant (e.g. NDC-4-USB).
Alternatively, Port 0 (OPTO IN 0 and ISO OUT 0) can be
used to connect a PC into the NMEA 0183 system by
using a serial port cable conforming to the following
1. A D-type female (socket) connector for the PC end of
the cable.
2. A minimum of 3 cores are required in a shielded cable.
Higher quality cable will yield higher performance (SNR).
Most typical cables have two twisted pairs inside. In this
case, use one pair for the TX line and one for the RX line.
Use the spare wire in each pair as ground, and connect
the cable shield to ground only at the computer end.
3. The TX of the NDC-4 should be connected to the RX of
the computer (standard D-type, pin 2) and the NDC-4 RX
should be connected to the TX of the computer (pin 3).
The GND of both IN 0 and OUT 0 on the NDC-4 should be
connected to the PC’s serial port ground (pin 5). See
“Figure 26 - DB9 Connection” on page 9 of the “Full user
manual” available on the CD and from www.actisense.
com for a diagram of this wiring connection.
Note: Wire colours are for guidance only.
© 2011 Active Research Limited
Page 9
USB Driver Installation
When using an NDC-4 with a USB cable it is necessary to
install the USB drivers. Any NDC-4 variant without a USB
cable can be ‘upgraded’ by purchasing a USB Upgrade
Kit from your dealer.
Follow these steps to manually install the drivers from the
Actisense CD or a copy downloaded from the Actisense
1. Open ‘Device Manager’ (from the start menu type
‘device manager’ in the search box, open it from the list).
The USB cable is not vital to the configuring or updating of
an NDC-4; Port 0 (OPTO IN 0 and ISO OUT 0) connected
to an RS232 port can perform exactly the same operations
if a USB cable is not available see “Other Connections”
on page 9.
The Actisense USB driver has been extensively tested
with Windows versions from Windows 98SE to Windows 7
and is proven to work with the NDC-4. The driver comes in
two parts and both are required for correct operation. The
first is the ‘USB serial converter’ driver and the second is
the ‘Virtual serial port’ driver.
The required Linux drivers are already included in the
Linux kernels from v2.4.20 and onwards. However,
Actisense has not been able to test the compatibility of
the NDC-4 with USB and this driver. Install instructions are
available on the CD and the Actisense website (www.
2. Find the NDC-4 under ‘Other devices’ and right click,
then select ‘Update Driver Software’.
Drivers for MAC OS X are provided ‘as is’ and Actisense
is unable to offer support for MAC related issues. To
download the drivers visit the Actisense website (www.
Installation Guide
Windows 7 and Windows Vista
The following instructions are for Windows 7. Although not
the same, Windows Vista users will be able to use this
information to install the drivers as well.
With an active Internet connection the process is very
simple. Connect the USB cable and Windows will
automatically download and install the latest driver from
Windows update. Both drivers are now installed and no
further steps are required.
3. If the CD is inserted select ‘Search automatically for
updated driver software’ and jump to step 4.
Without the CD select ‘Browse my computer for driver
When there is no Internet connection Windows will fail to
install the driver.
© 2011 Active Research Limited
Page 10
NMEA Data Multiplexer - NDC-4
4. Click the ‘Browse’ button and locate the folder that the
USB driver is saved (containing “ftdibus.inf”). Once
the folder is selected click ‘Next’.
Windows XP and Windows NT/2000
The following instructions are for Windows XP. Although
not the same, Windows NT/2000 users will be able to use
this information as well.
1. Connect the USB cable and Windows will automatically
open the ‘Found New Hardware Wizard’. If an active
Internet connection is available select ‘Yes, this time
only’, click ‘Next’ and go to step 4. Without an active
Internet connection select ‘No, not at this time’ and click
5. When the ‘USB Serial Converter’ driver has completed
the ‘Virtual Serial Port’ driver will need to be installed in
the same way. This time in ‘Device Manager’ right click
‘USB Serial Port’ and select ‘Update Driver Software’.
2. If using drivers from the CD, choose ‘Install the
software automatically (Recommended)’ and click
‘next’. Windows will search the CD and install the drivers,
go to step 4. If using drivers downloaded from the
Actisense website, choose ‘Install from a list or specific
location (Advanced)’ and click ‘Next’.
6. Repeat steps 3 and 4 to install the ‘Virtual Serial Port’
Now both drivers are installed see “USB Configuration”
on page 12 for details on how to find out which COM port
number has been allocated to your Actisense device as
well as how to change to a different COM port.
© 2011 Active Research Limited
Page 11
3. When using the drivers downloaded from the Actisense
website, it is important to unzip them to an easy to find
location. Make sure the ‘Include this location in the
search’ option is ticked, and use the ‘Browse’ button and
Now both drivers are installed see “USB Configuration”
on page 12 for details on how to find out which COM port
number has been allocated to your Actisense device as
well as how to change to a different COM port.
USB Configuration
To communicate with the NDC-4, the COM port number
that Windows has allocated to the USB port needs to be
determined. The following guide will walk the user through
this standard operation.
The Actisense NMEA Data Multiplexer, NDC-4 is
completely USB port independent: It can be easily
unplugged from one USB port and connected to another
available USB port on the same PC without the COM Port
number changing.
select the folder where the drivers have been extracted
and click ‘Next’.
This is very useful when the NDC-4 is working in unison
with a software program that is set up to use a particular
COM port, as the user does not need to re-select a different
COM port every time the PC reboots, or the cable is
swapped between two USB ports.
Locate and Change the Port Number
1. Connect the NDC-4 USB cable to a USB port on the
In Windows 7 and Vista; from the start menu type ‘Device
Manager’ in the search box, open it from the list.
In Windows XP; from ‘Control Panel’, select ‘System’, on
the ‘Hardware’ tab click ‘Device Manager’.
4. The ‘USB serial converter’ driver is now installed, click
‘Finish’ to complete the wizard.
5. Once complete ‘Your new hardware is installed and
ready to use’ will appear in the bottom right corner of your
Wait for the ‘Found New Hardware Wizard’ to appear
again. Repeat steps 1 to 4 to install the ‘Virtual Serial
Port’ driver.
© 2011 Active Research Limited
Page 12
NMEA Data Multiplexer - NDC-4
2. Expand the ‘Ports (COM & LPT)’ list by clicking on the
‘+’ sign (Windows XP and Vista) or the white arrow
(Windows 7). You will find the ‘Actisense NDC’ in the list,
followed by the allocated COM port number.
3. Double click on the icon for the ‘Actisense NDC’ and
the properties window will appear. Click on the ‘Port
Settings’ tab. There is no need to change any of the
settings here, the software package that opens the port
will specify the required values.
4. Click on the ‘Advanced’ button and choose a different
COM Port number if required (to make it compatible with
the software requiring the NDC-4 NMEA data).
Figure 4 - COM Port Numbers List
Windows remembers all previously connected USB ports
and lists all these as ‘in use’ even when they are not
connected. On the PC the screen-shot “Figure 4 - COM
Port Numbers List” the only ports that are actually ‘in
use’ are ports 1, 2 and 3 so all the other com port numbers
are available. Click on ‘OK’ button to save the new
© 2011 Active Research Limited
Page 13
Actisense PC Software suites
The Actisense NMEA Data Combiner hardware can be configured, monitored and tested using its own dedicated
software suite, ‘NDC Control Centre’. The NDC-4 can be updated / upgraded using the latest ActiPatch software suite.
This section provides a complete users guide to installing and uninstalling these two software suites.
These programs are currently only available for Windows NT/2000/XP/Vista/7, however, it has been proven possible to
use Control Centre and ActiPatch on a Mac running ‘VMware Fusion’ Windows emulation software.
Installing Actisense PC software
Replace the generic “<Product Name>” text below with
the name of the actual software you are installing: “NDC
Control Centre”, or “ActiPatch”.
1. Download the latest version of the software from the
Actisense website, or locate the files on the Actisense
CD included with the NDC-4.
2. If a previous version of the software has already been
installed, uninstall the previous version before installing
the new version. Refer to “Uninstalling Actisense PC
software” on page 15 for full details.
Note: For a complete fresh install, delete the install
directory. This will remove all previous settings. To keep
these settings, do not delete the directory.
Figure 5 – Install Options
3. If the program is contained within a zip file, extract the
three files (“<Product
Name>.001”, “<Product
Name>.002” and “setup.exe”) that are contained within
the zip file using any available unzip program to a
temporary directory (e.g. “C:\Temp”).
4. Double click on the “setup.exe” program file and
follow the on-screen instructions of the
standard Windows install program. The
install location can be change at this point,
however, the default location is normally
acceptable (refer to “Figure 5 – Install
Options” and “Figure 6 – Installation
Once the install operation is complete, the
temporary files and/or directory can be
deleted. Keep the original zip file safe.
5. From the ‘Start Menu’ navigate to the
‘Actisense’ directory and double click on
the ‘Program’ icon (refer to “Figure 7 ‘Start Menu’ Short-cuts” and “Figure 8
– ‘Start Menu’ Short-cuts”).
Useful Tip: If you access the program
regularly you can ‘copy and paste’ the
program icon from the Windows ‘Start Menu’ on to the
desktop or the ‘Quick Launch’ short-cut bar to create an
easy to access short-cut.
© 2011 Active Research Limited
Figure 6 – Installation Complete
Figure 7 - ‘Start Menu’ Short-cuts
Figure 8 – ‘Start Menu’ Short-cuts
Page 14
NMEA Data Multiplexer - NDC-4
Uninstalling Actisense PC software
Replace the generic “<Product Name>” text below with
the name of the actual software you are installing: “NDC
Control Centre”, or “ActiPatch”.
1. To uninstall the program, from the ‘Start Menu’ navigate
to the ‘Actisense’ directory and double click on the
‘Uninstall’ icon (refer to “Figure 7 - ‘Start Menu’ Shortcuts” on page 14 and “Figure 8 – ‘Start Menu’ Shortcuts” on page 14).
3. Once the uninstall operation has been requested, the
confirmation box (“Figure 9 – Uninstall Confirmation”)
will be displayed. Answer ‘Yes’ and the uninstall operation
will be performed automatically. After successfully
uninstalling the Actisense PC software, the uninstall
completion box will appear (“Figure 10 – Uninstall
Figure 9 – Uninstall Confirmation
Figure 10 – Uninstall Complete
4. In addition, the program directory can also be deleted to
completely remove the program. In this way all the program
files will be uninstalled in a clean and complete manner.
If however, you are going to install a new version after this
uninstall, you can keep the program directory and the
configuration file stored within it. In this way, all the user
settings you had for the previous version will be
immediately available with the new version.
© 2011 Active Research Limited
Page 15
Configuration of AIS
Talker 4
Talker 3
38400 Baud
4800 Baud
A Talker 1
38400 Baud
4800 Baud
38400 Baud
In Out
4800 Baud
Figure 11 – AIS Configuration with 38400 Baud Rate
Setting up the Hardware for AIS
Control Centre, supplied on the CD (or available for
download from Actisense website), allows a quick set-up
for AIS using the configuration file included.
To enable these settings on the NDC-4 click on the ‘Send
to Hardware’ button on BOTH the ‘Port Configuration’
and ‘Inclusion List’ tabs.
The AIS device should then be connected to the NDC’s
‘OPTO IN 2’ as shown in ‘Figure 21’, with any other
talkers connected as required. The device for receiving
the AIS data (chart-plotter or PC) should be connected to
‘ISO OUT 0’, or the USB port.
From the menu select ‘File → Load Configuration File’
and select “NDC-4 config for AIS.ini” file from the
install directory. Read the pop up and click ‘OK’.
This will change the settings for OPTO IN 2. The
configuration tab will set 38400 Baud (AIS requires NMEA
0183 HS). The Inclusion List is set to block all AIS data
from being sent to ISO OUT 1 which is typically kept at
4800 Baud. Filtering does not affect the USB/RS232 port,
all the AIS sentences will still be outputted on this port.
The remaining ports can be re-configured by the user as
needed using Control Centre. Refer to “Using NDC Control
Centre” on page 16 of the “Full user manual” available on
the CD and from for full detailed
information on how to use Control Centre.
Note: The use of AIS at Baud rates lower than 38400
cannot be recommended as this could cause random AIS
target data to be lost in areas of high target density.
© 2011 Active Research Limited
Page 16
NMEA Data Multiplexer - NDC-4
The NDC-4-ASW Autoswitch
The Actisense NMEA Data Multiplexer / Combiner /
Autoswitch (NDC) has been designed with the ability to
operate as a Multiplexer / Combiner OR an Autoswitch.
Setting the NDC-4 as an Autoswitch
The NDC-4 can easily be changed between being a NMEA
Data Multiplexer / Combiner and an NMEA Autoswitch
using Control Centre.
For systems that have multiple NMEA devices of an
identical type (e.g. two GPS’s or two depth sounders),
automatic selection of the highest priority device is
normally a vital requirement. However, the NMEA 0183
standard has no method of automatically switching
between different devices, so this requirement is usually
fulfilled with a manual changeover switch: not a very good
solution, but the only one available until now.
If the NMEA data from two (or more) devices are simply
combined together, the NMEA listener(s) will not be able to
differentiate between the various sources and will get very
confused, often jumping between them. If this creates a
‘jumping’ position fix, vessel safety is seriously affected.
The NDC-4 Autoswitch mode is the perfect solution to this
problem - automatically selecting a single device from the
multiple ‘same data type’ devices available.
Autoswitch mode will automatically select the highest
priority device from up to 4 connected input devices, with
NMEA port 1 as the highest priority through to NMEA port
4 as the lowest. This creates a system capable of
automatically selecting the next priority device if the higher
priority device fails for one of three reasons:
In the ‘Port Configure’ tab click on the button labelled
“Change To Autoswitch” to change the NDC’s operation
mode to Autoswitch.
• A complete failure to send any NMEA data.
• An invalid NMEA sentence checksum.
• If the validity flag(s) contained within the received NMEA
sentence indicate that this data is not valid and should
only be used with caution.
With the addition of two fully Baud rate configurable
outputs protected by ISO-Drive technology, that can also
incorporate NMEA filtering to remove any unwanted
sentences before the switching process, the NDC-4
Autoswitch mode is the most flexible available.
Having the ability to filter out NMEA data before the
autoswitch process can be particularly useful to avoid
unwanted sentences from causing the Autoswitch to
change input channels due to invalid data, leaving only the
required sentences to switch on.
If ordered as an Autoswitch, the NDC-4 will be preconfigured as an NDC-4-ASW and be ready to work out of
the box. Alternatively, any NDC-4 can be configured using
Control Centre to operate in Autoswitch mode.
© 2011 Active Research Limited
Figure 12 – “Change To/From Autoswitch” message
A warning message will be displayed, requesting that the
user confirm the request to change to Autoswitch mode.
Selecting ‘Yes’ will automatically send the new
configuration to the unit, and the NDC-4 will now Autoswitch
its inputs instead of Combining them.
To revert back to Combiner mode, click on the (same)
button (now labelled ‘Change To Combiner’). Again, the
user must confirm the operating mode change is required
and the NDC-4 will now Combine its inputs instead of
Autoswitching them. There is no need to click the ‘Send to
Hardware’ button, this configuration change is automatic.
Page 17
Troubleshooting Guide
This guide will concentrate on all relevant troubleshooting issues above simple cable connection faults. Therefore, the
cables between the NDC-4 hardware and any other devices should be checked as a matter of course, before continuing
with this guide.
Diagnostic LED
The NDC-4 hardware supports a tricolour diagnostic LED that indicates the current operating mode of the hardware, or
if an error has been detected during the self-test initiation process. ‘Table 1’ details what each LED colour represents
and if any user interaction is required.
LED Colour /
Flash Count
Mode / Error condition
Start up operation modes
LED is off
Power down mode
No flashing
Start-up mode,
No error
No flashing
Initialise and self-test mode,
No error
No flashing
Normal and no data mode,
No error
Running modes
Flashing (1-10 per
Normal and data Rx mode,
No error
No flashing
Flash updating mode,
No error
Error mode
Flashing (Once
every 4 seconds)
Error trap mode,
EEPROM memory error
Required User Response
The sequence below indicates a successful power-up of the
NDC-4 with no data on any of the input channels.
The NDC-4 has no power, confirm the battery is connected
correctly. For USB powered units, ensure the cable is
connected and the USB drivers are installed.
No response required. A normal operation mode that should
last for no more than 1.5 seconds. Any longer indicates an
error with the main program.
No response required. A normal operation mode that follows
after the Start-up mode and should last for approximately 1
No response required. A normal operation mode that follows
the Initialise and self-test mode. Indicates that no error was
detected during the self-test operation.
Also indicates that no data is currently being received by the
NDC-4 hardware.
Below are the other correct operating modes possible with the
No response required. A normal operation mode that indicates
that data is currently being received (on at least one channel)
by the NDC-4 hardware. Flash rate proportional to Rx rate.
No response required. LED will stay red for the duration of the
flash update operation (using Actipatch). Once operation
complete, NDC-4 hardware will be automatically reset.
Below is a possible error mode for the NDC-4. If the error
persists see “Returns Procedure” on page 20.
An error with the EEPROM memory has been detected during
the self-test mode.
Reset the NDC-4 hardware.
Table 1 – Diagnostic LED Colours
© 2011 Active Research Limited
Page 18
NMEA Data Multiplexer - NDC-4
The NDC-4 ISO-Drive output is a very flexible output that is RS485, RS232, RS422 and NMEA 0183 compatible.
Supply voltage
External power supply
Supply current from external source
(see note 1)
Supply voltage = 12v
Supply voltage = 24v
Supply voltage
USB powered
Supply current from USB (see note 1)
Supply voltage = 5v
Logical ‘0’/start bit
Maximum is under +35v overload
condition, Min @ 2.0v input level
Differential input voltage
Required level for NMEA to be detected
Galvanic isolation
Between input & output
Opto-isolated Flexible Input
Logical ‘1’/stop bit
Input voltage between +/Input current
Overdrive protection
Input Baud rate (ports 0 & 1 + USB)
Configurable Baud rate
Input Baud rate (ports 2 & 3)
Configurable Baud rate
Input Baud rate (port 4)
Fixed Baud rate
Logical ‘1’
Output short circuit current (note 2)
Logical ‘0’
At maximum load, differential drive
voltage reduces to 2.1v
Due to short circuit protection
Galvanic isolation
From Opto input and (USB) ground
Output Baud rate (ports 0 & 1 + USB)
Configurable Baud rate
Data propagation delay
Under no-overload conditions
ISO-Drive Flexible Output
Output voltage between ISO Out +/A and
ISO Out -/B (under no load)
Output current at max load of 100 ohm
Ambient temperature
Extended Actisense guarantee
Gland clamping range
Cable diameters accommodated
IP Rating
Table 2 – NDC-4 Specifications
All specifications are taken with reference to an ambient temperature (TA) of +25°C.
1. Current consumption measured under no-load conditions.
2. Short circuit may be applied indefinitely. The ISO-Drive output may be short-circuited directly to a 30 volt battery
supply without damage. A maximum current of 50mA will flow due to “polyfuse” auto-resetting fuse technology being
used in each output.
© 2011 Active Research Limited
Page 19
Order Codes
5 isolated inputs (4 NMEA HS), 2 ISO-Drive outputs
4 isolated inputs (3 NMEA HS), USB In & Out and 2 ISO-Drive outputs
NDC-4 base unit pre-configured for AIS
NDC-4-USB unit pre-configured for AIS
NDC-4 base unit pre-configured as an Autoswitch
Returns Procedure
Actisense prides itself on having a very low product return rate. In the unlikely event that you need to return a unit for
repair, it is important to follow these steps.
1. Download and install the latest Firmware version and Control Centre software from
2. Read through the “Troubleshooting Guide” on page 20 of the “Full user manual” available on the CD and from www. to see if your problem has a simple solution.
3. Contact Actisense Tech Support at the email address below for further support and an RMA number.
To qualify for an RMA number you will need to provide the serial number, date of purchase and where you purchased
the unit from. You will be asked to confirm the above steps have been attempted and the nature of the fault.
Any units returned without an RMA number will incur a delay in processing and may result in a charge dependant on
the guarantee status of the unit.
Company Information
Active Research Limited
5, Wessex Trade Centre
Ringwood Road
BH12 3PF
01202 746682 (International : +44 1202 746682)
Actisense on the Web: For advice, support and product details
(Actisense News and Product Updates)
(Actisense Product Updates)
(Actisense News and Product Updates)
(Actisense News and Product Updates)
“Actisense” is a registered trademark of Active Research Limited.
© 2011 Active Research Limited
Page 20
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