Connecting up AIS

Whether you have gone for a Class B transceiver or just a receiver, probably the most challenging part of fitting an AIS is connecting up to your plotter in order to display the targets you pick up.

It's relatively easy if you are using a PC based plotting package, provided you have a serial port you can hook up to.  Most laptops don't have RS232 ports these days, so you might need a USB/RS232 adaptor.  If you buy a Class B transceiver you will need to connect it up to a PC anyway in order to programme your MMSI and other vessel details into the unit.  Your dealer may be able to do this for you - we can!

Most current models of plotter can handle AIS data, although you might need a software update.  Check out the manufacturer's website.  Models more than a few years old may not be compatible.

Raymarine C & E series displays are compatible, provided the software is up to date.  The problem here, as with other plotters, may be finding a spare NMEA port that you can dedicate to AIS.  AIS operates at a higher data rate than normal NMEA (38.4kbps compares to 4.8kbps).  The Raymarine displays only have one NMEA input port and one NMEA output port.  AIS only needs an input port, but you can only set one data rate for input and output.  If you can connect all your other devices (instruments, GPS, autopilot) using the SeaTalk bus, then you can dedicate the NMEA port to AIS.  However if you are already using the NMEA port - for instance to connect to a non-Raymarine VHF DSC radio - then you will need to buy a multiplexer to join up the different NMEA devices.  Actisense make a range of these.  Another solution which might be cheaper is to use the Raymarine E85001 SeaTalk/NMEA/RS232 interface box to connect your standard NMEA devices into the SeaTalk bus, thereby freeing off the NMEA port on the display to use for AIS.

Other plotters, e.g. Standard Horizon, are supplied with multiple NMEA ports, but again you will have dedicate one IN/OUT port to AIS operation at 38.4kbps so if you run out of ports you may need to buy a multiplexer.  Note that a standard NMEA output can be wired to multiple NMEA inputs ("one talker, many listeners") but you cannot wire two outputs together, as they will fight!

The very latest instrumentation systems are using a universal network system called NMEA 2000.  Unless you can find an AIS receiver/transceiver which has a built-in NMEA 2000 interface, you will need a converter box to connect into this network.  Again Actisense can provide these.