1. Field of Invention
The invention relates to subscriber identity module (SIM) cards for portable electronic devices such as mobile and wireless telephones. More particularly, the invention relates to multiple subscription SIM cards in such portable devices.
2. Description of Related Art
Smart cards conventionally are used in many types of portable electronic devices, especially communication devices, for storing data, enabling access to a particular network or account, or configuring such devices to perform different functions. Such cards typically are made of plastic and have an electronic chip module mounted or embedded therein. The electronic chip module typically is a semiconductor chip including an integrated circuit with a microprocessor and memory, if appropriate, and contact or connection points for electrically connecting the terminals of the integrated circuit to the contact interface of the electronic device in which the card is inserted.
For example, many mobile or wireless telephones use cards with a subscriber identity module (SIM) to enable a user to access the wireless telephone network in a particular market or region of the country. The SIM typically is equipped with an electrically erasable programmable read-only memory (EEPROM) that has stored therein various information needed to operate and properly configure the SIM, and to identify the mobile phone user. Such information, which typically is thought of or referred to as a set of subscription parameters, includes the identity of the user and/or user account, and the network in which the user account is activated. For example, the set of subscription parameters stored in the SIM may include the user's mobile telephone number, an Integrated Circuit Card Identifier (ICCID), and an International Mobile Subscriber Identity (IMSI).
Some wireless telephone service providers have a different type of SIM card, for different service regions or markets throughout the country, e.g., when two or more regional service providers consolidate their operations. In such cases, it usually is not possible to simply consolidate the SIM supply because subscription information resident on the SIM is tied to the original region. Having different types or stock keeping units (SKUs) of SIMs often creates difficulties for the service provider and retailers. For example, mobile phone retailers have to maintain the multiple SIM SKUs if they are selling to mobile telephone customers in different service markets or regions.
Accordingly, it would be desirable to have available a single type of SIM card suitable for use in different service markets or regions without having to redesign existing network and IT systems.