Ok folks, been hunting for an answer to this and can find nothing definitive. Bought a 2nd hand 3GS after my buddy unpgraded (to a google phone booo hisss), and the problem being when I stick my o2uk payandgo sim in it I can use the data connection (ie EDGE) but the phone shows up with no bars of signal. It displays the carrier name ok, but wont let me make / receive calls or texts. As I said the data connection works perfectly (which I assume it wouldnt if the phone was barred). Im wondering is it because its a 2G sim card? I read some thing that apple only let you use 3G sims (altho i also read this isnt true) I have restored to the vanilla FW and havent jailbroken it but any suggestions would be appreciated!!! PS I have no 3G sim to try this!