"Meindert Sprang" wrote in
l.nl:

"Geoff Schultz" wrote in message
.. .
If you do a google search on this news group, you'll see that I
provided a link to a document that describes the protocol for normal
SeaTalk. The author was very responsive in some questions that I
had.

Yep. http://www.thomasknauf.de/seatalk.htm

While I can't tell you if there are differences between normal
SeaTalk and SeaTalk NG, I would bet that they are the same and that
main differences are in the physical and datalink layers.

It is indeed very different, NG is based on NMEA2000.
IMHO, RayMarine has too much invested in lots of software to be
making fundamental changes in the protocol.

Well, since NMEA2000 is based on CAN, it is relatively easy to run
NMEA2000 alongside some proprietary protocol on the same CAN bus and
call is Seatalk NG.

Meindert

Quoting from a RayMarine web site, "SeaTalk NG is an NMEA 2000 compatible
system, which can be interconnected to NMEA 2000 networks with an adapter
cable. It can also be interconnected to SeaTalk and SeaTalk2 networks for
backwards compatability with existing Raymarine installations."

Since this is backwards compatible with SeaTalk and SeaTalk2 networks, I'd
bet that the underlying protocol (application layer) is the same. While I
don't claim to know anything about the NMEA 2000 protocol, I would be
amazed if there wasn't some way to encapsulate a propritary message within
it without having to translate it to native NMEA 2000. This is done all of
the time in other networks.

So I'll go back to my guess that the application layer is the same but the
underlying layers (transport to physical) have been altered to NMEA 2000.

-- Geoff
www.GeoffSchultz.org