AT&T and T-Mobile

[TG1]

Guys,

If I buy an AT&T iPhone from ebay or Craigslist, can I use it on T-Mobile? I know they're both GSM carriers but I don't know what is involved in switching (unlocking, etc). Thank you.

 

[Applejuiced]

Guys,

If I buy an AT&T iPhone from ebay or Craigslist, can I use it on T-Mobile? I know they're both GSM carriers but I don't know what is involved in switching (unlocking, etc). Thank you.

No.
If its locked to AT&T it wont work with Tmobile even though they are both GSM.
You need to get an unlocked iphone or if you buy one that's locked you can then purchase an IMEI unlock after.

 

[Marcus72]

Jeff Benjamin tweeted this about unlocking an AT&T phone:

The folks at @cellular_medic are legit. Instant unlock of my iPhone 4S was completed within a few minutes. http://cellular-medic.com/


I'm might do this for my mom's iphone4 but I wonder if I can lock again after unlocking.

 

[Applejuiced]

Jeff Benjamin tweeted this about unlocking an AT&T phone:

The folks at @cellular_medic are legit. Instant unlock of my iPhone 4S was completed within a few minutes. http://cellular-medic.com/


I'm might do this for my mom's iphone4 but I wonder if I can lock again after unlocking.

No, once its officially unlocked with an IMEI service it will never lock again not matter how many times your restore or update the firmware.