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Installation instructions for Brookhouse NMEA multiplexer model AISC
General
This addendum describes connections and features of multiplexer model AISC where they are
different from the standard Brookhouse NMEA 0183 multiplexer. Please use the comprehensive
manual for the standard model for descriptions of general subjects such as the setup procedure,
USB connections, the optional LCD, backup switching etc.
Model AISC is specifically aimed at connection of an AIS receiver and other NMEA talkers to
Raymarine chart plotters, but there are many other uses as well. In this quick installation guide,
connection to a C- or E-series chart plotter is assumed. For use whith other than Raymarine C/E
series chart plotters, ignore the colour-coding on the front-label of the multiplexer and substitute
"chart plotter" for "C-series" or "C/E".
For C-series AIS support a software upgrade is available from Raymarine. The baudrate of the
NMEA port of the chart plotter has to be set to 38400 (AIS).
For the connection of the C-series display to the Brookhouse multiplexer a cable with a special 5-
pin connector is required, Raymarine product code R08004.
Brookhouse NMEA multiplexer model AISC is supplied pre-configured, i.e. it is not necessary to
execute the setup procedure, unless one or more of the extra features are required, such as
filtering or conversion of NMEA sentences or a different baudrate conversion option is required.
We recommend to install the multiplexer first without setup to check if all functions are working.
The setup procedure is described elsewhere in this installation instruction.
Connections
Make sure that the wires are inserted in the correct screw terminals that correspond with the
descriptions on the front label of the multiplexer. A mistake can easily be made if looking at the
connector and label from an angle. Count the terminal screws and corresponding descriptions
from the end of the connector if in doubt.
Power supply: 9-35V. For practical reasons, power may be obtained from the Raymarine
Seatalk connector. If the Seatalk option has not been installed in the mux, do not connect the
Seatalk signal wire, just power (red +, black -). Also see Seatalk below.
AIS receiver or transponder:
NMEA OUT + (38400 baud)
NMEA OUT -
Brookhouse NMEA 0183 multiplexers can be used with a large range of AIS receivers and
transponders. Unfortunately the output signal characteristics of the various devices differ
significantly and some do not comply with NMEA (RS422) or RS232 standards.
The multiplexer's NMEA input port for AIS is, like the other NMEA inputs, opto-isolated. The opto-
isolated port with the high baud rate 38400 requires signal characteristics, that fall in a narrower
acceptable range, than non-opto isolated ports. Therefore a given model AIS receiver or
transponder may work with a certain chart plotter or a computer port if directly connected, but
may not work if connected via the multiplexer. However, if the following simple instructions for
'conditioning' the output signal of certain receivers or transponders are followed, any compatibility
problems can be resolved.
Under the large green main multiplexer connector an insulated white wire (pig tail) can be found.
This wire is external, the mux enclosure does not need to be opened! The white pig tail can be
used to adapt the input impedance of the AIS input port for certain AIS receivers and
NMEA CH4 IN A
NMEA CH4 IN B
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Summary of Contents for Brookhouse NMEA AISC
- Page 1 USB connections, the optional LCD, backup switching etc. Model AISC is specifically aimed at connection of an AIS receiver and other NMEA talkers to Raymarine chart plotters, but there are many other uses as well. In this quick installation guide, connection to a C- or E-series chart plotter is assumed.
- Page 2 transponders. If this applies, remove the heatshrink insulation and combine the bare end with the AIS output signal wire in NMEA ch4 IN A of the multiplexer. Connect the following devices directly to the multiplexer’s AIS port (NMEA ch4 IN), without the white adaptation wire: Nauticast class A transponders.
- Page 3 Connections: Seatalk signal wire (yellow) ST Yellow Signal Seatalk shield (-12V) ST Shld – Seatalk +12V (red) ST Red + Note: If the Seatalk option has been ordered, it has been enabled in our workshop. This means that CH1 NMEA IN cannot be used for a NMEA talker connection. To disable Seatalk and free up CH1 for NMEA, the setup procedure has to be executed.
- Page 4 The yellow and brown NMEA OUT wires of the C/E-series plotter can stay disconnected and instead, 38400 bps computer output can be converted to 4800 bps., e.g. to control the auto pilot in track mode. If the multiplexer is to be connected via USB, the blue wire under the green mux connector has to be inserted in the terminal marked “Yellow –...
- Page 5 8 and 2 above 8 and 3 above Etc. A separate document describing the baudrate conversion options in more detail is available from Brookhouse. Important: In spite of the filtering out of the AIS data, the bandwidth of the 4800 output may potentially still be insufficient to transmit all data from the 38400 output data stream.
- Page 6 Filtering / Conversion of NMEA sentences A separate description is available from Brookhouse and on the website. The main application of this feature is converting or filtering NMEA output data from the C-series. The format of NMEA sentences can be altered to suit NMEA listeners that require a different version of NMEA or entire sentences can be filtered out to remove redundant data.