Editing SIM card (section)

== Design ==
[[File:Smartcard chip structure and packaging EN.svg|thumb|SIM chip structure and packaging]]
There are three operating voltages for SIM cards: {{nowrap|5 V}}, {{nowrap|3 V}} and {{nowrap|1.8 V}} ([[ISO/IEC 7816]]-3 classes A, B and C, respectively). The operating voltage of the majority of SIM cards launched before 1998 was {{nowrap|5 V}}. SIM cards produced subsequently are compatible with {{nowrap|3 V}} and {{nowrap|5 V}}. Modern cards support {{nowrap|5 V}}, {{nowrap|3 V}} and {{nowrap|1.8 V}}.<ref name=":1" />

[[File:Sim Chip.jpg|thumb|{{convert|4|x|4|mm|adj=on}} silicon chip in a SIM card which has been peeled open. Note the thin gold bonding wires, and the regular, rectangular digital memory areas.]]

Modern SIM cards allow applications to load when the SIM is in use by the subscriber. These applications communicate with the handset or a server using [[SIM Application Toolkit]], which was initially specified by [[3GPP]] in TS 11.14. (There is an identical ETSI specification with different numbering.) ETSI and 3GPP maintain the SIM specifications. The main specifications are: ETSI TS 102 223 (the toolkit for smart cards), ETSI TS 102 241 ([[application programming interface|API]]), ETSI TS 102 588 (application invocation), and ETSI TS 131 111 (toolkit for more SIM-likes). SIM toolkit applications were initially written in native code using proprietary APIs. To provide interoperability of the applications, ETSI chose [[Java Card]].<ref>{{cite web |title=ETSI TS 102 241: UICC API for Java Card™ Release 13 |url=https://www.etsi.org/deliver/etsi_ts/102200_102299/102241/13.00.00_60/ts_102241v130000p.pdf |access-date=8 August 2019 |archive-date=8 March 2021 |archive-url=https://web.archive.org/web/20210308204923/https://www.etsi.org/deliver/etsi_ts/102200_102299/102241/13.00.00_60/ts_102241v130000p.pdf |url-status=live }}</ref> A multi-company collaboration called [[GlobalPlatform]] defines some extensions on the cards, with additional APIs and features like more cryptographic security and [[Radio-frequency identification|RFID]] contactless use added.<ref>{{cite web |title=Specifications Archive: Secure Element (Card) |url=https://globalplatform.org/specs-library/?filter-committee=se |website=GlobalPlatform |language=en |access-date=8 August 2019 |archive-date=31 July 2019 |archive-url=https://web.archive.org/web/20190731103515/https://globalplatform.org/specs-library/?filter-committee=se |url-status=live }}</ref>