Cell phone unlocking is done for one reason: remove a mobile phone’s carrier restriction so that it may be used with another carrier. If you’re thinking of unlocking your phone, read on. There’s one thing you should find out before you proceed to unlock your cell phone – and that is whether or not your phone can use the service of your target cell phone provider (the carrier to which you wish to switch).
Some people immediately unlock their cell phone – only to find out later on that they can’t actually use it with the carrier they want. It could be that their cell phone has support only for the GSM network standard, whereas their target carrier uses the CDMA network technology.
One of the basic steps for unlocking your cell phone, therefore, is discovering whether your handset is a GSM phone or a CDMA phone.
Do You Have a GSM or a CDMA Handset?
In the United States, cell phone providers mainly use one of two mobile communications standards: GSM (Global System for Mobile Communications) and CDMA (Code Division Multiple Access).
[Note: CDMA is actually a technology – a channel access method – rather than a mobile communications standard like GSM. CDMA 2000 is one of the mobile phone standards that use the CDMA channel access method. For the purposes of this discussion and in the interest of simplicity, however, this article uses CDMA and CDMA-based network technologies like CDMA 2000 interchangeably.]
Cell phones for GSM networks are card-based. That is, they are used with a Subscriber Identity Module (SIM) or SIM card. Thus, if a GSM phone is unlocked, you should be able to use it with any SIM card provided by any network with GSM support. In the US, the wireless providers that use the GSM platform include AT&T (also Cingular, which is now part of AT&T) and T-Mobile.
Cell phones that operate on CDMA networks (at least in the US), on the other hand, are traditionally card-free. In other words, they are pre-programmed with the CDMA network’s service settings and could not be used with any other network or carrier without first being reprogrammed. It is for this reason that CDMA networks (at least in the US) must provide their subscribers with handsets.
When a CDMA network subscriber wishes to change phones, his information (his subscriber identification programmed in his old phone) is transferred to the new phone, so the old phone basically becomes useless (unless it is programmed for a new user). In the US, the wireless providers that use CDMA include Verizon and Sprint.
The Real Question: Does your phone support GSM or CDMA?
If your cell phone is card-based or has card-access, it should be easier to switch networks. After you unlock your phone, chances are high that you can use it with another network.
If your phone does not have card access, you’ll find it hard to switch to another carrier. Phones without card access have to be reprogrammed to work with your new network.
Rule of Thumb: GSM to GSM, CDMA to CDMA
If you use your phone with a GSM network, you should have no problem using that phone with another GSM network after unlocking your phone. All you need to do is switch SIM cards.
If you use your card-based phone with a CDMA network, you should have no problem using that phone with another CDMA network after unlocking your phone. All you need to do is switch R-UIM cards.
Now, there are phones that offer even greater flexibility. New-generation cell phones usually have support for all types of network platforms. After unlocking, you should be able to use that phone with any carrier using any mobile communications standard. All you’ll need to do, in this case, is to get the card from your new network. This card can be a SIM card if it is a GSM network, an R-UIM card if it is a CDMA network or a smart card (known as the Universal Integrated Circuit Card) which comes loaded with the necessary application so it can work with a GSM, CDMA or any other type of network architecture or platform.
[Note: The UICC can contain SIM provisioning so it can work with GSM networks, CDMA Subscriber Identify Module (CSIM) so it can work with CDMA networks or Universal SIM (USIM) provisioning so it can work with UMTS (Universal Mobile Telecommunications System) networks. Carriers that issue a UICC with their handsets do so mainly to let their subscribers access other carriers on a different network platform when these subscribers are traveling to a place where the home network is unavailable. Of course, the subscribers’ access to other networks in this case is subject to roaming charges.]
To find out if you can use your cell phone with your target carrier or wireless provider (that is, if your phone has support for the mobile network technology used by your target network), check your phone’s specifications in the phone manufacturer’s website. You must do this before unlocking your cell phone.