With its nascent 3G network launch in parallel with the first smartphone that makes use of that network, T-Mobile has a lot to prove to the world. The tech community has been abuzz with hope for the one of the first carrier-adopted open source phones, the G1, also called the Dream and made by Windows Mobile manufacturer HTC. Probably a far cry from the friendly T-Mobile we once knew, but T-Mobile is placing a cap on the monthly amount of “unlimited” data that G1 users may utilize at 1 GB. According to Engadget Mobile, exceeding the 1 GB limit allows the carrier to throttle your data speed, making future use of your device much, much slower to the tune of 50 Kbps, which is much slower than EDGE data speeds which top out at around 200-250.

While wireless carriers have been flexible and issued warnings even before taking any threats heavy-handed, T-Mobile’s short limit may give incentive for other major carriers to lower their limits. The industry soft-cap currently for wireless data hovers around 5 GB per month.

Hopefully, the cap is just one way to thwart demand for 3G services initially for the carrier to build capacity. In comparison, with AT&T’s launch of the 3G iPhone, there were service outages and problems on the carrier side due to unprecedented demand for 3G data, forcing the carrier to add towers rapidly to meet demand in some metropolitan areas. Even then, there were still unhappy users claiming inconsistent data connectivity, slower than advertised data speeds, and voice and data problems on occasion.