Smart cards provide secure user authentication, secure roaming, and a platform for value-added services in wireless communications. Presently, smart cards are used mainly in the Global System for Mobile Communications (GSM) standard in the form of a SIM card. GSM is an established standard first developed in Europe. In 1998, the GSM Association announced that there are now more than 100 million GSM subscribers. In the last few years, GSM has made significant inroads into the wireless markets of the Americas.

Initially, the SIM was specified as a part of the GSM standard to secure access to the mobile network and store basic network information. As the years have passed, the role of the SIM card has become increasingly important in the wireless service chain. Today, SIM cards can be used to customize mobile phones regardless of the standard (GSM, personal communications service [PCS], satellite, digital cellular system [DCS], etc.).

Today, the SIM is the major component of the wireless market, paving the way to value-added services. SIM cards now offer new menus, prerecorded numbers for speed dialing, and the ability to send presorted short messages to query a database or secure transactions. The cards also enable greeting messages and company logotypes to be displayed.

Other wireless communications technologies rely on smart cards for their operations. Satellite communications networks (Iridium and Globalstar) are chief examples. Eventually, new networks will have a common smart object and a universal identification module (UIM), performing functions similar to SIM cards.