Any intention to review GM270?

[Dave]

No, not exactly. NMEA 4800 usually is the preferred baud rate for 90% of GPS Receivers, and usually come switched to NMEA mode and at 4800, but some will run at different baud rates under NMEA, some like the Holux GR-230 will run at 38400. You can't necessarily run all GPS's on the complete range of bauds under NMEA, and the same goes for SiRF too, it really depends how the manufacturer has implemented the chipset.

4800 is obviously the slowest baud rate, but the amount of data that the GPS Receiver is sending down the cable, doesn't create a bottleneck at 4800, so there's a lot less data being transferred than you would think.

Switching to say SiRF 57600 will transfer the same data quicker, and give the Pocket PC more time to pause (milliseconds), but used to help more on things like Navman sleeves, where the GPS chip was very close to the Pocket PC processor and could cause an RF noise interference.

Destinator used to prefer SiRF but has run in NMEA quite happily since Destinator 2.

One thing I usually find in my tests is if I try to run at SiRF 57600, where you may be fluctuating around a 5-7 sat fix, dropping to 3 or 4 once in a while, you actually notice at higher baud rates, just how many times you drop to a 3 sat fix, which means seeing more no signal messages which can then cause more hassle with re-routing. If you have a strong signal, running at SiRF 57600 can be good, but personally I prefer NMEA 4800.

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