3uk sim not working

[barryo987]

Hi,
i have a ulocked iphone 2g and have been using a orange uk sim in it for 6 months, but now im in a contract to 3uk and when i put the sim in the phone it says invalid sim, sim failer any ideas how to gret the sim to work? thanks

[Rip]

I didn't think it was possible for an iPhone to work on the 3 network, only Orange, O2, Vodaphone and T-Mobile.

Or maybe it's just data that won't work on 3. There's certainly a limitation that is peculiar to 3.