Are you familiar with phones that have a SIM card reader installed? These types of phones are available across the world, but only through the GSM phone network in the United States. In other words, you need to have service through either T-Mobile or AT&T. The rest of the providers only are affiliated with CDMA phones and do not have SIM card readers. In case you were wondering, you will not be able to unlock your cell phone without having a SIM card, also called a "Subscriber Identity Module." It is simply a removable memory card that can be removed from your phone and transferred to a different phone whenever someone with a GSM plan gets a new phone.

Each and every SIM card reader is able to interpret the information from the SIM card, which is able to store personal information regarding an individual's phone plan and their calling minutes. People on the GSM cell phone network are required to have their cards placed into their SIM card readers before their service will function. You will be disconnected from either your T-Mobile or AT&T service if you do not have your card inserted correctly into your phone. The SIM card itself functions as a memory storage unit from which your provider can wirelessly track your phone usage.

If you have a plan that utilizes a "subscriber identity module," then you will only be able to use phones that have a SIM card reader. The best part about having these readers is that you can pop in your card anytime you want to make a call and take it out if you do not want anybody to use your phone. Most people leave their cards in their phone until they upgrade to a new cell phone. In theory, you could have hundreds of different phones and use a new phone every day as long as you transferred your SIM card to the SIM card reader of the phone that you wanted to use.

It is estimated that over one-billion people use phones that operate with SIM card readers. Not only do people in the United States have access to this technology, but it is actually more popular in other countries. The CDMA cell phone providers are much less popular across the world simply due to the fact that they have enjoyed using what the GSM phones are able to offer. It is much easier to upgrade your cell phone when you are working with a SIM card reader in your phone as opposed to the CDMA phones. The reason that it is easier to work with these phones is because you do not need to take your phone back to a cell provider and have a worker "deactivate" your old phone and "activate" your new one.

The SIM card reader is easy to use and is very self-explanatory. Most people that use phones with them enjoy that they have the ability to switch to any new phone at anytime that they wish. You should be the judge as to whether you are going to want to get service with GSM or CDMA. Make sure that you have a GSM plan through T-Mobile or AT&T before you even attempt to unlock your phone and switch to a new one without the help a cellular phone technician.

More Cell Phone Articles: