On Fri, 21 Dec 2007 21:09:06 GMT, (Richard
Casady) wrote:

On Sun, 16 Dec 2007 06:02:17 -0800 (PST),
wrote:

I like Peter's cable
splitter idea and may give it a shot using an old serial to USB
adapter.

I have never been able to figure out why they use more than two wires
for a serial connection.

Casady

For an NMEA-0183 connection from GPS to computer, only two wires are
required: ground, and data GPS-computer. To upload waypoints or
other data from computer, a third wire is needed for computer - GPS.

For other applications, additional signals may be required - some
applications use (or used) "hardware handshaking" - extra signals to
permit each end to tell the other whether or not they were ready to
transfer data.


--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca