[iRoninTMO]

The number of Bands is infinite, although once you get past 1900 you're not looking at a lot of viable space for PCS/Cellular communications. Hence Nextel's panties in a twist over VZW wanting them to get 2.4 GHZ spectrum (ref: the rebanding plan to solve the problem with cellular signals interfering with emergency responder transmissions). It would take a lot of power to push a 2.4 ghz radio wave a long distance. GSM is designed to operate in the 900/1800 and 1900 bands. The 800 band (which is technically 850, because it doesn't use the full spectrum band). It came into being when Cingular and AWS decided to go GSM. It's how they're phasing out their D-AMPS (analog cellular service), by slowly (very very very slowly) rebanding it as GSM. The only problem? GSM isn't designed to function efficiently in that band. Hence the recent problem with Cingluar and the Motorola v600. The phone pretty much looks at 850, and then promptly throws up on its shoes. I am a bit biased, I work for T-Mobile, however we HAVE been doing GSM for quite some time. Anyways, hope that clears up the confusion, or creates more of it.

Adam