Raystar 120 NMEA Vs Seatalk

[exapp]

Hello,

I am aware that there are two different versions of this GPS senson. One NMEA version (E32026) with a fitted 6 pin plug and a Seatalk version (E32025) with bare wires. Both versions have the exact same colours of wires cable.

Question is are these the exact same unit once you leave out the plug, i.e. if i snip off the plug from an NMEA version and wire it to a Seatalk as per the instructions for the seatalk version will it work.... ditto for the seatalk version can it be wired to work as NMEA just like the newer Raystar 125

Exapp

 

[isandell]

I doubt it. NMEA and Seatalk are very different schemes. NMEA is like the serial port on your computer and Seatalk is like the ethernet network connection.

Ian

 

[exapp]

Yes but the raystar 125 can do both depending on how you wire it.
I'm hoping the 120 is the same and that the actuall sensor unit is identical on the seatalk and nmea versions.

If this is the case the only real difference is one has a plug and the other is bare wires...if the plug is snipped off hey presto I've just converted the nmea part number to sealtalk. All that is left to do is wire it correctly.

 

[Gypsy]

Yes NMEA & SeaTalk are different and the NMEA is close to RS232 as expected by computer serial ports and in ASCII protocol but SeaTalk is not ethernet. It is 0/12v serial data at 4800b but it is inverted compared to NMEA and is in Hex not ASCII.

It is possible that the 120 GPS can output both if different wires are used but we need someone with detailed knowledge of the model to clarify that point, however I suspect not.

 

[Gypsy]

I just looked at the 120GPS manual which can be found here. There are two different models as you mention and yes they use the same colour wires and yes the Seatalk out is on yellow just as the NMEA is on yellow....BUT as I mentioned in my earlier response there is a significant difference in the protocols.

There will be hardware and software differences inside the unit to drive the different data protocols and the inverted data of SeaTalk.

How can I be sure? I have designed a product for Seatalk and had to research the subject and the differences. As both models use the same yellow wire for their output, it is not possible to drive both NMEA and Seatalk from the same circuit unless there was some kind of jumper or switch to make the selection.

It looks like Raymarine decided they needed a dual protocol model and produced the 125 if it can do both.