I have a blackberry through work that is on the mycingular.blackberry network. The Blackberry has a built in phone but the phone service is not covered through work.

Can I take my own cingular or ATT wirless SIM card from my own phone and use it in the blackberry?

GB

yes or no..
Cingular has a crappy setup..
it might work if your voice plan is primary and your BB will not work for internet.
if the voice plan is secondary then your own SIM may not work on BB because it will connect to primary plan first..
T-mo does not care and they have no concept of pri/sec feature which is good..

'joginder', I'm not sure what you mean by primary or secondary. Will you explain that to me?

'geobrick', when I got my 1st BlackBerry, all I did was put my SIM card in and I had no issues with it not working, until I started having problems with the BB itself. The only way I could see it not working is if your company has some kind of IT policy on it that would not allow it to work, if it is even possible to do that.

A Co-worker in another state told me he tried but it was asking for some 4 digit SIM card code. I'm not sure that SIM cards have codes.

You can enable SIM security which means that it asks for a PIN (not the same as the Blackberry PIN) when you power up the device.

You should be able to place and receive calls but the data features won't work unless you have a Blackberry data plan on your account.

I put an active at&t card in my bb....phone worked perfect...no data.

If he has a SIM security code, could it be a default code that it comes with? I have never set a security code on my SIM so maybe there is a default code.