Glossary Definition for: SIM

SIM stands for Subscriber Identity Module. The tiny SIM card is mandated on GSM and LTE networks and identifies you to the network.

Swapping your SIM into a new phone essentially moves your service and phone number to that new device.

SIMs come in a range of sizes – Full-Size is extinct, but Mini-SIM, Micro-SIM, and Nano-SIM are all in common circulation. Because the Mini-SIM was the standard for so long, that size is often referred to as “full sized” or “standard sized.”

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Using cutters and adaptors, you can transplant larger SIM cards into devices that have smaller SIM slots, and vice-versa.

SIM cards are often tricky to find but can usually be found behind the removable battery of some devices, or in a small tray that can be ejected from the side of a phone with a pin.

NOTE: An eSIM is an embedded SIM chip built into a cellular device that can be provisioned via software, eliminating the need for the awkward physical card. Devices such as the cellular Apple Watch have ditched SIM slots entirely in favor of an eSIM, and the 2018 iPhone models were the first to take eSIM usage for smartphones mainstream.

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