On Fri, 18 Feb 2005 14:15:12 -0500, Jack Erbes
wrote:

Peter Bennett wrote:
(hit the wrong button on the previous post...)
Garmin recievers only use the Garmin protocol for uploading and
downloading waypoints and routes, and for uploading Garmin's
proprietary maps or charts. Many non-Garmin programs can use the
Garmin protocol for waypoint and route transfers.

In my general inexperience with things Garmin, I may have some mistaken
impressions about the effect of the Garmin protocol. I thought data in
the Garmin proprietary format would not be read or used by an
application not specifically written to use it. In other words, if an
application was looking for NMEA data strings, it would not read any of
the Garmin proprietary data strings would it?

That is correct. You have to manually switch the GPS receiver between
Garmin and NMEA modes. Some programs (like Ozi Explorer) know enough
to switch modes and baud rates (Garmin protocol uses 9600, NMEA uses
4800) when you ask them to transfer waypoints.

One marine charting program is too smart - if you tell it you have a
Garmin receiver, it insists on using Garmin protocol instead of NMEA
to get the real-time navigation data. If you want to feed NMEA data
from the GPS to an autopilot or DSC radio, you have to lie to the
program, telling it you have a Generic NMEA source, so you can leave
the GPS in NMEA mode.

And I'm not trying to argue the point, I'm trying to learn more. Just
in case I have not already established my level of expertise here, I'll
say know that I know about enough to be dangerous. :)

Jack

--
Peter Bennett VE7CEI
email: peterbb4 (at) interchange.ubc.ca
GPS and NMEA info and programs: http://vancouver-webpages.com/peter/index.html
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