Are the 7100T and 7100g phones interchangeable if unlocked?

I am using a 7100T on t-mobile and the service is really poor. My associate's 7100g in Cingular indicates more than 10 dbm signal strength.

If I change to Cingular can I just put their SIM card into the unlocked 7100t?

ALSO - I noticed that the phones are a lightly different shape. Does anyone know if the insides are identical or are there possible differences in the antenna?

Thanks

The phone will work fine, if unlocked, on Cingular. Cingular has 850MHz towers and if you connect to one of them, your indoor reception will be better -- the range is shorter on the lower frequency, but building penetration is better.

Yeah, once your 7100t is unlocked. You should be able to insert the sim card from your Cingular phone and it should work properly.

But you will have to pay more for the monthly data service.

I went with Tmo but am returning my 7100 due to poor service indoors, but I thought Cingular in my NY area pigybacked Tmobile's towers, so would there still be 850mhz service for Cingular?

I would probably switch to Cingular if that was the case, otherwise it is back to Nextel's 7520.