Used Cell Phones: GSM Versus CDMA

Finding a cellular phone and carrier that fits your needs is never easy. There are some basic things you have to know about your phone and cellular carrier like coverage areas, data availability, data transfer speed, roaming etc.. One of the most important things you should look for in a cellular carrier before you chose one is what network technology they use.

Most cellular carriers In the U.S. (T-Mobile, Sprint, Verizon, AT&T and others) use either CDMA, or GSM and sometimes both. What do GSM and CDMA mean, and which one is better for your needs? let's first understand the meaning and the differences between the two.

CDMA stands for Code Division Multiple Access. Using codes, in CDMA the data and voice are separated from signals - leaving more space for data transfers. That is why CDMA is favored by 3G users - as they send and receive multimedia messages or using wireless broadband to access the internet. CDMA technology uses wide frequency-range to transmit voice and data.

GSM or Global System Mobile (or Group Special Mobile) is the most widely used network technology around the world - dominating as much as 80% of the worldwide cellular networks market, and even greater percentage of the market in Europe. With GSM, roaming between CSPs (Carrier Service Providers) is more common than with CDMA - which is why GSM users can use their mobile devices in almost every part of the world. GSM is categorized as a second generation cellular system because the speech channel is digital (analog audio signals are converted into digital signals), as well as the signaling.

Here are some factors you might want to check before choosing one over the other:

SIM Card: GSM SIM (Subscriber Identity Module) Card is a memory card that identify the user and saves his information, phone book, calender entries and more. SIM Cards can be taken out of one device and put into another very easily, so that your info, data and calling plan can be carried into a new handset within a minute. That's one of the major reasons for people preferring GSM SIM cellular phones over CDMA phones. On the other hand, most CDMA CSPs have a database (on the CSPs computers) that stores your data, and transfers it to a new device upon your request - easily. That gives CDMA carriers an advantage: user's info and phone-book recovery in case the phone is lost or stolen.

Domestic / International Usage: if you're a business man going on a business trip abroad every once in a while, or just travel a lot, GSM is right for you. With GSM being used by almost 80% of cellular phone users around the world, it is considered more accessible than CDMA. you'd be able to use your quad-band GSM phone all over Europe and in most parts of Asia, while multi-band is not available with CDMA - which reduces the use of CDMA overseas.

There are more differences between the two, of course, but these few are the most significant and affect the user the most. Make sure you do your research before choosing your cellular service provider, and remember to ask what network technology they use.