How do you tell if a phone is unlocked

[jtvang125]

When I turn it on I don't see anywhere on the screen telling me which carrier it's tied to. There's no sim card in it right now but when I put in my old, old att sim card it just says inactive sim but doesn't say att anywhere either. Does this mean it's an unlocked phone?

 

[caivoma]

What kind of phone? Where did you buy it?
when it said inactive sim for old att sim card, it could be unlocked or could be locked into ATT. Do you have a friend that have Tmobile? just borrow their sim and put it in the phone.

 

[EvilYoda]

yeah, easiest way is just to ask your friend's to borrow their SIM cards for a second. I doubt you could find any indication outside of a service menu.