A SIM card, short for subscriber identity module, is a small integrated-circuit card that securely stores the data a mobile phone needs to identify and authenticate a subscriber on a cellular network. The German company Giesecke and Devrient produced the first SIM cards in 1991 for the launch of the GSM digital mobile network by the Finnish operator Radiolinja. SIM cards have since shrunk through several standard sizes, from the original credit-card-sized card down through the mini, micro and nano formats, and increasingly to the embedded eSIM built directly into a device rather than inserted as a removable card.
Facts
SignificanceThe first SIM cards were supplied to Radiolinja for the launch of the world's first commercial 2G GSM network, making the card the subscriber identity component of digital mobile telephony. 1 FAQs
What information does a SIM card store?
A SIM card stores the subscriber identity number (IMSI), the card's own serial number (ICCID) and encryption keys.
A SIM card stores the data a network needs to recognize and authenticate a subscriber. One source lists the International Mobile Subscriber Identity, known as the IMSI, the unique serial number of the card, known as the ICCID, and encryption keys used for subscriber authentication and network access.
Connections
In Field
Source SIM card, Wikipedia
Sources
1. SIM card, Wikipedia
History and procurement, manufacturer clause
The first SIM card was manufactured in 1991 by Munich smart-card maker Giesecke+Devrient
History and procurement, final clause
who launched the world's first commercial 2G GSM cell network that year.
In Field: Computer Engineering, Introduction
SIM cards are also used in various satellite phones, smart watches, computers, or cameras.
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