How to Unlock a Cell Phone or Smartphone

Chances are, your cell phone is tethered to one particular
service provider. If you try to leave that company, your
phone won't work. It's locked. If you travel to another
country and try to use another company's cell phone service
on your old phone, that won't work either. Locked again.

It doesn't have to be this way, though. Depending on what
kind of phone you have and what company you purchase cell
phone service from, you might be able to unlock your phone.
Then, you'll have the freedom to use the same phone with
different companies, or switch phone numbers and service
accounts.

If you've ever wondered what the difference between a locked
and an unlocked cell phone is, or if you've ever wondered if
your phone can be unlocked, or how you can do it, we'll
explain it to you in this article. Plus, we'll tell you why
having an unlocked phone can be a good thing, and whether or
not it's legal.

Cell Phone Unlocking: Can your phone be unlocked?

There are two cell phone technologies that are used by the
majority of the world's mobile phone service providers:
Global System for Mobile communication (GSM) and Code
Division Multiple Access (CDMA). If you have a CDMA phone,
then your phone is not unlockable. End of story. However, if
your phone operates on a GSM network, then it might be
unlockable.

What's the difference? GSM phones use subscriber identity
module (SIM) cards. A SIM card is a small card that's
inserted into the phone. It contains all your contacts and
settings, and it's linked to your account. You can take the
SIM card out, put it into another phone, and if someone calls
your number, the new phone will ring. You can also put
a different SIM card in your unlocked phone, and your phone
will then work with whatever phone number and account is
linked to that card. CDMA phones have no SIM cards and must
be authenticated by the service provider, which makes
unlocking a phone impossible.

If a phone is locked, the service provider has installed some
software on the phone that ties the subscriber ID number on
the SIM card to the serial number of that particular phone.
If the SIM card and phone serial number don't match, the
phone simply won't work. The SIM card won't work in other
phones, and the phone won't work with other SIM cards.

If you live in North America, you can usually determine
whether your phone is GSM or CDMA based on the service
provider you use. T-Mobile and AT&T use GSM, while Verizon
and Sprint use CDMA. In Europe, almost all phones are GSM.

How can you tell if your phone is already unlocked? In
Europe, unlocked phones are more common. In fact, many
countries have cell phone portability laws that make it
illegal for a company to lock a phone to a specific account
(though these laws seem to change frequently). In North
America, fewer phones are sold unlocked. If you received
a phone for free or at a very low price when you signed
a contract for your cell phone service, your phone is almost
certainly locked.



There's an easy way to find out for sure: Find a friend whose phone is known to be unlocked. Have your friend place his or her SIM card in your phone, and then call your friend's number. If your phone rings, you know your phone is unlocked. If your phone simply generates an error message, then it's locked.