Unlocking the G1?

[divestoclimb]

It's the dual band part you need to be looking at, IIRC. The HSDPA numbers. 1700 and 2100 are the 3G numbers. The others are edge numbers. (Over-simplifying a bit maybe here but...)

ATT is on freq. 1900, I believe. Not compatible.

This is my understanding as well. AT&T wanted to get started with building their 3G network in the US before one of the two frequencies had been vacated by whomever was using it before, so they used a non-standard frequency to get going. T-Mobile chose to wait and deploy their US 3G network on the "right" frequencies.

Aren't T-Mobile's 3G frequencies the same as the ones being used in the rest of the world? Theoretically you could unlock this phone, pop in a local SIM and get 3G assuming the local provider supported it... I'm not sure if this is true with AT&T's 3G phones like the iPhone.

[DesignDawg]

This is my understanding as well. AT&T wanted to get started with building their 3G network in the US before one of the two frequencies had been vacated by whomever was using it before, so they used a non-standard frequency to get going. T-Mobile chose to wait and deploy their US 3G network on the "right" frequencies.

Aren't T-Mobile's 3G frequencies the same as the ones being used in the rest of the world? Theoretically you could unlock this phone, pop in a local SIM and get 3G assuming the local provider supported it... I'm not sure if this is true with AT&T's 3G phones like the iPhone.

I think the G1 frequencies DO work in Europe, yes. But I also think the iphone has these frequencies. (At least 1700). That's how you can use a hacked iphone on TMobile's network.