GSM, or Global System for Mobile Communication, is a global cell phone network standard. It is the most used cell phone standard in the world, and is especially popular in Europe. Compared to other network standards, such as the competing CDMA system, GSM has several distinct advantages and disadvantages.
One of the biggest advantages of the GSM network is its use of SIM, or subscriber identity module, cards to identify users' phones. SIM cards are small chips that contain information like a subscriber's phone number, contacts, preferences and other data. Users can move a single SIM card from one phone to another, making it easy to transfer service between phones without losing important data.
One disadvantage of GSM phones is that they must be large enough to incorporate a SIM card slot. This can place limits on the design of GSM-enabled phones, while cell phone manufacturers can work more freely on designs for phones that are intended for other cellular standards and require no SIM card.
The GSM network extends around the world, allowing users of GSM phones to place roaming calls from more locations that users of CDMA phones. Telecommunications suppliers began building the GSM network in the mid-1980s, meaning that today it is more extensive and technically refined than the less-mature networks, including CDMA.
Lack of American Presence
Another significant disadvantage to the GSM network is its relative lack of visibility in the United States. While US cell phone provider AT&T uses GSM technology, most other US cell phone companies still rely on CDMA. Because of the recent growth in US cell phone use, and the emergence of more complex cellular devices like smart phones, GSM's lack of an American presence puts limits on its growth as a worldwide network leader.