MiniSIM

MiniSIM, commonly referred to as standard SIM, is the original size of subscriber identity module used in mobile devices on GSM networks. It predates the microSIM and nanoSIM formats and is sometimes described as the standard or full-size SIM in contrast to newer, smaller variants.

Physical characteristics and interface: A miniSIM measures 25 by 15 millimeters and has a thickness of about 0.76 millimeters. It is a removable card that uses the ISO/IEC 7816 contact interface to communicate with the mobile device. The card contains a microcontroller and memory that store essential data and perform security operations.

Data stored and purpose: The SIM stores identifying and security data such as the International Mobile Subscriber Identity (IMSI), an authentication key (Ki), and the integrated circuit card identifier (ICCID). It may also hold network provisioning information and basic contact storage. During operation, the mobile device communicates with the network using the data on the SIM to authenticate the subscriber and to establish encryption and service access.

Provisioning and security: The SIM is provisioned by a mobile network operator and often protected by a Personal Identification Number (PIN). If the PIN is entered incorrectly, access can be blocked and the SIM may require a PUK code to recover.

History and status: MiniSIM was widely used in 2G and early 3G devices but has largely been superseded by smaller microSIM and nanoSIM formats. While many older devices still accept miniSIMs, newer devices typically use the smaller sizes. Adapters are sometimes used to fit a miniSIM into a device designed for a smaller form factor, though this can affect reliability. Some devices retain compatibility through SIM reconfiguration or eSIM options, which do not rely on physical card size.