Meindert Sprang wrote:

"Pascal Goncalves" wrote in message
om...

Anibody can tell me the diferences betwen V3.1 and V2.0? Or better,
who have the NMEA 183 specs can send me a copy?


The NMEA specs are copyrighted material and can only be obtained, at a cost,
from www.nmea.org.


I'm a little confused about this. There are numerous explanations of
the NMEA sentences on the net, examples are Peter Bennet and Glenn
Baddeley's web sites:

http://vancouver-webpages.com/peter/nmeafaq.txt
http://home.mira.net/~gnb/gps/nmea.html

Those seem to contain most or all the NMEA 0183 information that anyone
would want. If you paid NMEA's sort of costly membership fee and
acquired their not too cheap specs, what more would be gained by doing
that?

Do you have to be a NMEA member to use the standard in firmware? Or
software?

Jack

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

"Jack Erbes" wrote in message
...
I'm a little confused about this. There are numerous explanations of
the NMEA sentences on the net, examples are Peter Bennet and Glenn
Baddeley's web sites:

http://vancouver-webpages.com/peter/nmeafaq.txt
http://home.mira.net/~gnb/gps/nmea.html

Those seem to contain most or all the NMEA 0183 information that anyone
would want. If you paid NMEA's sort of costly membership fee and
acquired their not too cheap specs, what more would be gained by doing
that?

Those sites contain only a part of the existing NMEA sentences and are
pre-V3.0. So if you can live with this info, no problem. But if you want to
develop software that gets the most out of modern equipment, it would be
wise the have the latest version available. For instance, on the sites you
mention, none of the descriptions of the GPRMC sentence show you the mode
indicator field which tells you if the fix is valid or not.

The standard expands as new equipment comes on the market. A nice example is
AIS. This required the definition of a whole new set of sentences, covered
from V3.0 and upwards.

Do you have to be a NMEA member to use the standard in firmware? Or
software?

No. Anyone can buy the standard from NMEA. But members get a discount.

Meindert

"Meindert Sprang" wrote in message
...
"Pascal Goncalves" wrote in message
om...
Anibody can tell me the diferences betwen V3.1 and V2.0? Or better,
who have the NMEA 183 specs can send me a copy?

The NMEA specs are copyrighted material and can only be obtained, at a
cost,
from www.nmea.org.

I read somewhere that
the V 3.1 alows for more than one talker: this is true?

No. Data from more than one talker can only be combined using an NMEA
multiplexer.

Meindert



Hi,
Meindert is right, a multiplexer is necessary to combine talkers.
However, with the various versions of NMEA sentences and the resulting
compatibility problems, it is advantageous to purchase an "intelligent"
multiplexer, one that allows you to do NMEA conversions, insert extra fields
in a sentence, etc.
There is one such multiplexer on the market that allows you to convert
entire sentences "on the fly", e.g. to convert a GGA to a RMC sentence, or
to insert extra fields, to make your older equipment compatible with NMEA
3.01. It also allows you to suppress sentences that your software doesn't
need (filtering), change NMEA ID's and many more other functions. Of
course, the checksum is re-calculated and replaced after changes have been
made to the original sentence. All these functions are controlled by
user-definable directives in a script file and can be uploaded to the
multiplexer in a simple way.
The same multiplexer has a "data pacing" feature to slow down fast talkers,
such as some electronic compasses. It will also add extra safety to the
integrated system by switching automatically to a backup GPS when the
primary GPS stops outputting NMEA data. This happens more often than one
would think and usually at a time it is most inconvenient. So, this is
actually a multiplexer taken a few steps further.
All to good to be true? A Google search for "NMEA mux" will get you there.

Wout

Take a look at http://vancouver-webpages.com/peter/nmeafaq.txt

Regards,
Gerard van Toornenberg, Lemmer @ N 52° 51.352', E 05° 41.834' Nederland
Email :
Homepage : http://members.home.nl/gvantoornenberg/


"Pascal Goncalves" schreef in bericht
om...
Anibody can tell me the diferences betwen V3.1 and V2.0? Or better,
who have the NMEA 183 specs can send me a copy? I read somewhere that
the V 3.1 alows for more than one talker: this is true?

I am interested specifically in the RMB, RMC, BWC, XTE, DSC, DSE, to
interface autopiots and VHF/DSC radios.

Thanks

Pascal Honcalves

"Gerard van Toornenberg." wrote in message
...
Take a look at http://vancouver-webpages.com/peter/nmeafaq.txt

That info is pretty old. More like NMEA-0183 V2 or so. V3.1 has a lot of
sentences with extra/new fields added.

Meindert

You are right some are outdated.

Gerard

"Meindert Sprang" schreef in bericht
...
"Gerard van Toornenberg." wrote in message
...
Take a look at http://vancouver-webpages.com/peter/nmeafaq.txt

That info is pretty old. More like NMEA-0183 V2 or so. V3.1 has a lot of
sentences with extra/new fields added.

Meindert

Thank You, I had forgoten that only with a NMEA multiplexor I can have
more than one talker. I have the folowing situation: my gps is
sending NMEA messages to my AH autopilot, and the gps is receiving
Depth (DBT) from an Navman depth sounder. Aditionaly, I have a laptop
witch is reciving NMEA from the gps, for real time ploting, using some
software. If I add a VHF/DSC radio, sending and receiving NMEA to/from
gps, what would hapen?

My gps is a Garmin Gpsmap276C, witch now (3.1) includes a very
interesting interface with VHF/DSC, that can show the position of all
boats nearby (if they are DSC/VHF ready), so that I will see the
positions of all boats in the map screen, this would be useful in a
flotilha cruising for example,or pheraps to see ships in the scren? I
think this is not dependent of the Mayday function, witch is suported
too, but shows diferent symbols, colors and alarms.

In this case I will have more than one talker?

Thanks

Pascal



"Gerard van Toornenberg." wrote in message ...
You are right some are outdated.

Gerard

"Meindert Sprang" schreef in bericht
...
"Gerard van Toornenberg." wrote in message
...
Take a look at http://vancouver-webpages.com/peter/nmeafaq.txt

That info is pretty old. More like NMEA-0183 V2 or so. V3.1 has a lot of
sentences with extra/new fields added.

Meindert

I don't know which VHF/DSC radio you have, but all the ones I have
looked at only receive GPS data. ICOM, Uniden, West Marine only have a
GPS in lead. My Garmin drives four listeners, auto pilot, Pactor IIe,
Uniden VHF/DSC and computer with Nobeltec Navigation software. The
computer is the only device that can transfer data to the GPS.
krj


Pascal Goncalves wrote:

Thank You, I had forgoten that only with a NMEA multiplexor I can have
more than one talker. I have the folowing situation: my gps is
sending NMEA messages to my AH autopilot, and the gps is receiving
Depth (DBT) from an Navman depth sounder. Aditionaly, I have a laptop
witch is reciving NMEA from the gps, for real time ploting, using some
software. If I add a VHF/DSC radio, sending and receiving NMEA to/from
gps, what would hapen?

My gps is a Garmin Gpsmap276C, witch now (3.1) includes a very
interesting interface with VHF/DSC, that can show the position of all
boats nearby (if they are DSC/VHF ready), so that I will see the
positions of all boats in the map screen, this would be useful in a
flotilha cruising for example,or pheraps to see ships in the scren? I
think this is not dependent of the Mayday function, witch is suported
too, but shows diferent symbols, colors and alarms.

In this case I will have more than one talker?

Thanks

Pascal



"Gerard van Toornenberg." wrote in message ...

You are right some are outdated.

Gerard

"Meindert Sprang" schreef in bericht
...

"Gerard van Toornenberg." wrote in message
...

Take a look at http://vancouver-webpages.com/peter/nmeafaq.txt

That info is pretty old. More like NMEA-0183 V2 or so. V3.1 has a lot of
sentences with extra/new fields added.

Meindert