Updated at 4:20 PST with response from T-Mobile.
After a busy weekend where it made its very unofficial debut, HTC's Nexus One entered into full legitimacy Monday with approval by the Federal Communications Commission. The FCC documents also reveal that the device will support North American GSM bands (850 and 1900) and T-Mobile's 1700 3G network.
Though at least one Nexus One sighted this weekend was running on an AT&T SIM card, the support for T-Mobile's 3G would leave AT&T out of the running for the Nexus One, at least for now. The two carriers use the same GSM bands for voice calls, but their 3G networks are incompatible.
T-Mobile said it doesn't comment on rumors or speculation, but its participation in the Nexus One (aka the "Google phone") would send a mixed message concerning how the device would be distributed to consumers. The Wall Street Journal reported today that Google would directly sell the Nexus One as an unlocked unsubsidized model. Distribution through a carrier channel, however, would mean that Google wouldn't sell the Nexus One on its own.
Details and specs on the Nexus One remain mostly unknown, but the FCC documentation also shows that the handset would support hearing aids, a microSD card slot, Bluetooth, and 802.11b/g Wi-Fi.