Connections

• According to the GSM Association, there were 3.5 billion GSM mobile connections worldwide as of 2009. This represents about 81 percent of the total 4.3 billion mobile connections in the world. In addition, there are about 2 billion users of GSM technology worldwide. China was the largest market for GSM, with 370 million users. Russia was second with 145 million, followed by India with 83 million and the United States with 78 million.
  
  

Subscriber Identity

• Typical GSM handsets use a Subscriber Identity Module (SIM) card that stores the user's account information. This means that a user traveling to a foreign country can rent a handset, plug in his SIM card, and gain immediate access to the network.
  
  

Texting

• GSM handsets use the short message service (SMS) technology, which allows them to send text messages of up to 160 characters to other users.
  
  

Frequencies

• Handsets using the GSM technology operate on several frequency bands in the U.S., including 850 MHz and 1.9 GHz.