SIMkaartes

A SIM card, short for Subscriber Identity Module, is a small, removable smart card that securely stores the International Mobile Subscriber Identity (IMSI) number and its related keys used to identify and authenticate subscribers on mobile telephony devices. This allows a mobile phone to connect to a cellular network. The SIM card acts as a digital passport for a user on a mobile network, enabling them to make calls, send messages, and access data services. It is typically inserted into a dedicated slot or tray within a mobile phone, tablet, or other compatible device.

SIM cards come in various sizes, with the most common being standard (Mini-SIM), micro (Micro-SIM), and nano (Nano-SIM). The smaller sizes were developed to accommodate the increasingly compact designs of modern mobile devices. eSIMs (embedded SIMs) are a newer technology where the SIM functionality is built directly into the device's hardware, eliminating the need for a physical card. Users can activate an eSIM by downloading a profile from their mobile carrier. The SIM card stores essential information such as the user's phone number, network subscription details, and contact lists, although many users now store contacts in their device's internal memory or cloud services.