"Joe Wood" wrote in message
...


Meindert Sprang wrote:
My 'all time favourite' would be a marriage between NMEA-0813 and
SeaTalk
and some other features. Use a CAN bus driver, (passive '1' level/active
'0'
level), use the same text-based NMEA type sentences (easy to debug), use
the
collision detect feature of SeaTalk and increase the speed to a few
hundred
kbit/second. And when need be, switch to a binary variant of NMEA.

Meindert



I can't agree. Hardware is cheap to develop relative to software. A
handful of hardware engineers can keep armies of software developers
busy indefinately. This is epecially true for low run items like boat
and ship electronics.

Especially with low run items, I think any other interface than plain old
RS-485 or CAN is bad.
A 100baseT interface is indeed easy to design, but costs quite a lot in
components on low runs and needs much more processor power than RS-485 and a
'modified' NMEA. I mean, take a log sensor: a paddle wheel, a hall sensor,
an op-amp a very small micro and a RS-485 driver and you're done. Cheap. Now
do the same with ethernet. You need magnetics, a big connector, a larger
micro and a large enternet chip. (And I mean large in comparison with a few
SO-8 packages).

Meindert