GPS Baud rate?

Serial (RS-232) devices usually start at the lowest usable baud rate in order to be able to assure that they will talk to each other. There are many variances on how fast you can push this connection - quality of cable, length of run, signal strength of both the DTE and DCE ends (data and carrier equipment), external RF interference, etc, etc, etc.

4800 bps is a nice slow standard to start with. The reason that your device starts there is because it will most probably work at that speed. If you try bumping your speeds up at either end (in unison of course) until you have problems, go back a notch - find a good medium and stick to it. I successfully run at 9600baud all of the time, and you really shouldn't need to go any faster to transmit/receive simple NMEA data such as waypoints and track logs. If you were downloading maps and such, then you may want to go for the highest speed you can - up to (probably in your case) 110kbps - which is fast as most UARTs (serial data communication chips) in laptops work.

V8Diesel, The NMEA string provided by your GPS only appears once every second. The Transmit time between your GPS and laptop is (at 9600bps) for a standard nmea string only about .2 of a second. For the other .8 of a second nothing is happening!! ( computer waiting for next gps string!) therefore, the standard settings are 9600 bits per second(baud rate), being a very reliable and robust speed. If you increase Baud rate, there are no advantages, as I mentioned earlier, nmea gps strings only appear every second....

Hope this helps...

Jarrod.

Never had any luck getting my Magellan to function higher than 4800 but if it works go for it ,can't do any harm.
Regards Charlie

Actually if you turn on all the possible NMEA strings (RMC,VTG,GSA,GSV,GGA and VTG) they comprise more than the 480 characters that 4800 baud can transmit in one second.

When you use moving map software the sooner the laptop gets the string from the GPS the sooner your position will update. While the difference is small it can be noticed.

I run my current GPS at 19,200, and the previous one (A Holux GM210) at 38,400 or 57,600 (both worked).

As has been said 4800 was the chosen standard and is enshrined in the NMEA standard. It will work with anything.

Some chipsets you cannot change the baud rate. I have had SirfStarII and SirfStar xtracII GPS and changed the baud rate but I could not get the Evermore chipset GPS to run at anything but 4800.

Peter

G'day V*Diesel

It's simple really. If your GPS & PC can be set at identical baud rates they will be able to communicate using RS232. I had a garmin 12xl that ran fine at 9600. I now have a GPSmap76, kind regards to the thief that stole the old one, and it doesn't allow anything other than 4800 in NMEA mode as far as I can tell.

cheers