How does carrier locking work? Can anyone with a SIM from that carrier use the locked device?

[fullscore21]

If a phone is locked by AT&T, does it mean anyone with an AT&T SIM card will be able to use that device? Or is the SIM card only compatible with that specific device, unusable on other devices (even devices under the same carrier)?

I'm wondering because I'm thinking about selling my locked AT&T phone, but I don't want the buyer to receive it and find out their AT&T SIM won't work on my phone ID because they aren't on my cellphone plan.

Are SIM cards assigned to SPECIFIC devices? Or can anyone with a SIM from the phone's carrier use the phone?

 

[hallux]

If a device is carrier-locked, it can be used on that carrier only but on any account. Obviously if the device was bought subsidized on contract, your contract needs to remain in good standing (or the phone paid off) in order for the buyer to not lose the ability to use the device (the carrier will then block the device itself if your account defaults).

Again, the device can be used with ANY SIM from the carrier it's 'locked' on, AT&T in your case.

The other thing you can do, which would make the phone more attractive to more people, is get it unlocked by AT&T, this also means you've satisfied the terms of the purchase as AT&T will not unlock the device if you haven't.

 

[fullscore21]

If a device is carrier-locked, it can be used on that carrier only but on any account. Obviously if the device was bought subsidized on contract, your contract needs to remain in good standing (or the phone paid off) in order for the buyer to not lose the ability to use the device (the carrier will then block the device itself if your account defaults).

Again, the device can be used with ANY SIM from the carrier it's 'locked' on, AT&T in your case.

The other thing you can do, which would make the phone more attractive to more people, is get it unlocked by AT&T, this also means you've satisfied the terms of the purchase as AT&T will not unlock the device if you haven't.

Thanks!