In article . com,
Akka wrote:

OK, just so I understand: if I want to upload waypoints from the PC, I
just send them on the same serial interface on the computer (COM5 or
whatever) that I'm using to download the nav data from the GPS, using
one of the Garmin GPS input ports? I'm a little confused by your
reference to GARMIN/GARMIN proprietary format for loading waypoints,
as I don't have a Garmin chartplotter, just an ordinary HP laptop.

Rob


Hmmmm, seems to be a communications failure here..... GPS's talk out
their serial ports in specific "Languages", like NEMA0180, NEMA0182,
NEMA0183, NEMA2000, Garmin/Garmin, ect. Each "Language" may or may
not, be backward compatab;le with any older "Language" depending on
a varity of things. NEMA's up thru 0183, use the same Physical
Layer, but have progressivly more information available, in the
Communication Strings. NEMA's up thru 0183, are Half Duplex
Monodirecional with only ONE Talker, (Master) and many Listener (Slaves)
allowed on each Directional Physical Layer. It is also a Current Loop
type Physical Layer, that can be used to drive an RS232 Serial Input on
a Computer, with Sort Cable runs, and minimum connections.

Garmin/Garmin uses the a Company Specific "Language" that isn't
compatable with ANY of the NEMA "Languages" but will usually run on the
Physical Layer of the GPS's output and some, if not most, Computers
Software packages can understand the Garmin/Garmin "Language", which is
a true Full Duplex Bidirectional Master/Slave protocol. Garmin has
designed the Protocol (Language) in such a way that Software that uses
it to communicate, are very efficent in moving data, to, and from, the
GPS's with a minimum of overhead, and Bandwidth used. On later Garmin
GPS's the complete Display and GUI "Graphical User Interface" is
available on the attached computer, via Software.