luc wrote:

Meindert,

thanks again for clarifying lots. I'm learning here, and getting a
good laugh at the same time. It sounds like what I want to do is not
only doable, but relatively easy. What is the software side of this?
So far, instruments are communicating, but then when you connect to a
laptop, then what does one need to read this stuff? Chart plotter
style software?

what a great way to learn,

thanks,

Luc

Here is a place that will answer a lot of questions:

http://gpsinformation.net/

Check out the 3rd party software link there to find a number navigation
and GPS related softwares. For marine navigation, Seaclear II is a
great piece of freewa

http://www.sping.com/seaclear/

Jack



--
Jack Erbes in Ellsworth, Maine, USA - jackerbes at adelphia dot net
(also receiving email at jacker at midmaine.com)

In article .com,
"purple_stars" wrote:

and it runs
over an rs-232 interface USUALLY, but it doesn't have to.

Actually NEMA0183 has a Hardware Spec as well as a Protocol, and the
Layer 1 Spec is not RS232, but a previous spec to RS422, which is a
Current Loop running at 4800 Baud. The Previous NEMA0181 spec is
where the Layer 1 Spec was originally introduced. NEMA0181 was
designed to drive AutoPilots.

Bruce in alaska
--
add a 2 before @

"luc" wrote in message
oups.com...
I am an NMEA neophyte. I am trying to connect my Raymarine speedo,
depth, and wind indicator. They use SeaTalk. Apparently, SeaTalk is
not NMEA language. I thought the point of NMEA was to make multiple
manufactures equipment communicate, much like MIDI (musical instrument
digital interface) works for electric guitars, keyboarsd, and
synthesizers.

I have a Garmin GPS, which does have some NMEA capabilities. I would
like to connect it to my ICom VHF, for the DSC feature. I would also
like to connect my sounder to the GPS to show depth on the Garmin. Is
this possible? Does anyone know where to get more information about
NMEA and connecting these various devices? I've already learned a bit,
but have a long way to go.

You could connect the NMEA output from the GPS to the NMEA input of the VHF
and at the same time connect the NMEA output from a sounder to the NMEA
input of the GPS.

If your sounder is part of the Raymarine setup, you can use one of my
multiplexers to convert Seatalk into NMEA.

Also, from what I hear, the issue of "daisy chaining" is somewhat
resolved by the new NMEA 2000 protocol. Easy connectors, simple
wiring. Still, NMEA reminds me of DOS based computing. (it amazes me
that windows has DOS underlying it!)

NMEA2000 is not a daisy chain, it is a similar setup like an ethernet
network where every device can send it's data on the network and listen to
any data on the network. A collision detection mechanism prevents data
corruption when two devices want to talk at the same time. It is based on
CAN.

Meindert

is it possible to have more than one NMEA input to the GPS?

luc wrote:
is it possible to have more than one NMEA input to the GPS?


NMEA 0183 is single sender, multiple listeners. So any listener ("INPUT"
) MUST NOT be be connected to two or more senders.

So the answer is yes; you can connect more than one NMEA input to your
GPS NMEA output.

However, as Meindert's webpages show so clearly, there are issues when
one of the manufacturers has not kept exactly to the standard (which a
lot do).

One obvious way to violate the standard is to tie in the GPS output,
some real NMEA inputs _and_ a RS-232 input port on a laptop. The RS-232
port violates the electrical spec of NMEA, and your results might go
either way (works or not; or even worse: works some of the time).

This mess is why there are NMEA multiplexers: to get multiple talkers
sending data to the listener, and to translate NMEA into/from
RS-232/USB/Bluetooth.

--
Kees