The phone needs activating before you do anything.

Mine had problems when I first put my sim in. Can't remember exactly what now but it wouldn't pick up networks properly.

I had to take it to the O2 shop where they simply swapped my original sim for a 3G sim :thumbs:

i've never had an issue with using other O2 sims in an iPhone, obviously changing network requires you to unlock the iPhone (hence why an orange sim won't work, unless the phone is unlocked already).
I'm guessing you have an O2 signal where you are? Also what O2 sim are you using - PAYG? Another contract sim?

Like others said, try plugging it up to iTunes and see if that works - you shouldn't have to (as the iPhone usually works out of the box, certainly did with mine) but it won't hurt trying. Alternatively, you could do a restore from iTunes and see if that corrects it.
Settings shouldn't matter as you'll still get a signal and be able to call, texting/mms/internet will be a different story but plenty of info about if you a google.

That or it needs to be unlocked to use a non-iPhone sim in it.

You need to activate it in iTunes before it will work.

Think you need to do somthing with iTunes

[Edited on 07-01-2010 by oceansoul]

Have a look around the 02 website. There's probably something in the FAQ's.

but I can get passed the screen saying no network emergency calls only

I think you need to activate it?

You might need to change the settings on it.

My uncle (a builder) had a new phone on contract (iphone) 3g 8gb

being a builder he sticks to his old nokia waterproof shitty thing


so hes given the o2 iphone to my sister

we've put a simcard in it (o2) and it says no network service, does the same with my orange sim.. any ideas?