On Fri, 1 Sep 2006 19:07:49 +0200, "Meindert Sprang"
wrote:

Well, let's define one!
It would be interesting though to see how the major brands transfer NMEA
over ethernet. But indeen, UDP is the best way since it is also a
connectionless/broadcast protocol just like NMEA0183 and NMEA2000.

Agreed. I use UDP in my stuff. It makes it easy to keep the network
"open" in that any device on the subnet can grab the data and use it.
For that reason, I just send the NMEA sentences one at a time, with no
mods or higher level constructs that a listener would have to be aware
of. The only "gotcha" (and it's irrelevant to the vast majority of
uses) is that all the routers I've looked at block UDP broadcasts from
going off the subnet, for good and sufficient reasons. If you want to
broadcast to another subnet you have to target the UDP to a specific
address on that subnet and let it repeat the message as a broadcast on
that subnet. At least, that's the way I solved the problem in my
stuff.

Unfortunately, I've found that most of the potential listeners to the
NMEA data I'm making available are so busy making everything
proprietary that this is less of a benefit than I hoped.


-----------------------------------------------------------------------------------------------------------
Glen "Wiley" Wilson usenet1 SPAMNIX at world wide wiley dot com
To reply, lose the capitals and do the obvious.

Take a look at cpRepeater, my NMEA data integrator, repeater, and
logger at http://www.worldwidewiley.com/