I want to operate the TRX with a Raymarine C60 multi-function-display. For that I want to use the NMEA interface at which the GPS datas are supplied at the moment. (easyTRX in use with an chartplotter, which has only one NMEA input (most of the Raymarine devices).

The easyTRX is a class B CS AIS transceiver. The easyTRX is conform to the current class B norms and certified by the BSH. All by the BSH certified transceivers are mostly similar.The reason for this is, because they have to fulfil the norms, which are very detailed and strict. The norms are defining nearly everything beginning form the type of the case over EMV – values, power supply, synchronisation of the AIS radio network, channel access, channel state, displays, procedure types, and actions for the suppression of neighbour-channels, broadcasting power until the shoe-size oft he user.

This is why the devices are only different in the design, the graphical user-interface for programming the MMSI and the basic applications for displaying AIS. Different are mostly the flexible factors like the detail grade of the manual, the completeness of the connection cables, and necessary accessory and also the availability of useful accessory devices splitters with class B capability and combined VHF/GPS antennas. Also the service of the manufacturer which ours is the best one! All class B transceiver have in common, that they need an own GPS. This is necessary because the normally existing GPS antennas deliver NMEA GPS data. This NMEA data are generally not exactly enough in reference to their time-base. A typical class B AIS telegram takes 25ms. Within 1 ms the class B transceiver hast o deliver his „beam“. In order that sent telegrams are not overlapping, every sender has to keep an exact for sending. The date for sending has to be more accurate as the telegram. The date of sending is determined at ca. 100µs by the class B sender. This is only possible, when the sender gets the raw data from the GPS antenna and not NMEA data, which are only accurate to 1/10 s. This is the reason.

You cannot put both, the easyTRX with a data rate of 38400 Baud and the GPS NMEA data with 4800 Baud, to one interface of the C70. In your case of usage you will need a multiplexer, which increases the 4800 Baud of the NMEA GPS data to 38400 Baud.

Why do I have to buy an additional built-in GPS with the easyTRX and connect an external GPS?

easyTRX 1. Generation >>>

All class B transceiver have in common, that they need an own GPS.

This is necessary because the normally existing GPS antennas deliver NMEA GPS data. This NMEA datas are generally not exactly enough in reference to their time-base. A typical class B AIS telegram takes 25ms. Within 1 ms the class B transceiver has to deliver his „beam“. In order that the sent telegrams are not overlapping, every sender has to keep an exact for sending. The date for sending has to be more accurate as the telegram. The date of sending is determined at ca. 100µs by the class B sender. This is only possible, when the sender gets the raw data from the GPS antenna and not NMEA data, which are only accurate to 1/10 s. This is the reason. For a reliable operation GPS datas on a µs base are needed. With the explanation above you need 2 GPS antennas. One with NMEA data for your chartplotter and one for the easyTRX.

I would like to plug in the easyAIS 1 (Nasa-AIS by AWNiemeyer) with my notebook. You delivered a NMEA-cable. May I connect the easyAIS via the serial port and an USB-adapter directly on the notebook?

FAQ: easyAIS 2nd. Gen. >>>The easyAIS can be connected with a pc (this is also in the manual on page 12).

Connection of the easyAIS to the pc: Please connect the white-orange cable with the pin 2 of the SUB D 9-pole connector (female) and the orange cable with the PIN 5 of the SUB D 9-pole connector. It is very urgent, that you take the right PINS. They are hardly readable at the plug, but they are signed. After that, please install the USB serial adapter on the pc. Then you can connect the SUB D 9 connector with the adapter.

Please note the interface must be configured correctly: 38400 Baud, 8/N/1.

Can I pass through only GPS NMEA data or can I also pass through other NMEA data 4800 by means of the into the easyAIS integrated upconverting multiplexer?

Our integrated multiplexer is converting NMEA 1083 signals from 4800 Baud to 38400 Baud, not depending whether it is a GPS or another signal. If you pass your fast heading signal through to our easyAIS into your C80, everything will work smoothly. (It works for one unit from which the signals are passed through to the NMEA input of the C80.)Please don’t forget to configure the NMEA input at your plotter to 38400 Baud. You do not need a multiplexer at all.

Does the pass-through of additional NMEA-data only work in one direction?

1) Passing through of further NMEA data: The data is passed through only in one way that means pc data do not go back through easyAIS into the GPS.2) Reduction of the baudrate: it is generally o.k. Many of our customers are using the lower baudrate of 4800 because of different facts. To do that we have had a jumper on the board in the first generation of easyAIS products. Now we do it by a special start up procedure which is described in the manual of the easyAIS 2nd generation. But it takes a little bit longer with 4800 baud until you have all data on your pc.

The typical result of the lower baudrate: For example if you have 160 targets (at the moment we know the Rotterdam harbour is the only one which has such a high number of targets) With 4800 Baud it takes about 40 seconds until you get all the dynamic data onto your display. If it is no problem for you to wait to receive the objects onto your display, you can use one port with 4,8 kB. But if you would like to have the objects in real-time you should prefer to use maybe a 2nd port where you can get the easyAIS NMEA data by 38400 Baud.

Can I connect my easyAIS-TRX2 to Lowrance HSD 5 or HSD 7 Units?

FAQ: General >>>

The plotters Lowrance HDS 5 and HDS 7 feature a differential type input for connecting external NMEA devices and therefore they require a bipolar signal at these points. Most commercially available AIS devices, transceivers and receivers are equipped with standard unipolar outputs. Our devices are built according to this standard.

The easiest way to solve this problem is to connect a capacitor  in-line with the NMEA positive signal between the NMEA output of the AIS device and the NMEA input of the chart plotter. Thus a 100% function is ensured.

Please use the inputs and outputs at 38400 baud, to avoid traffic congestion and potential loss of data at high AIS traffic volumes.

Please, note the following requirements for the capacitor:

  • Value: 100nF
  • Ceramic or plastic, does not matter
  • Voltage:> 16V DC
Select Language
Back to top