What is a SIM card?
SIM card, also known as a subscriber identity module, is a smart card that stores data for GSM cellular telephone subscribers. It is a portable memory chip used mostly in cell phones that operate on the Global System for Mobile Communications (GSM) network. These cards hold the personal information of the account holder, including his or her phone number, address book, text messages, and other data.
SIM cards also serve as storage for SMS messages and the user’s contacts. Current SIM cards can store up to 250 name/number pairs and up to 50 SMS text messages.
SIM cards come in four standard sizes including
- Full-size (85.6mm × 53.98mm × 0.76 mm)
- Mini-SIM (25mm x 15mm x 0.76mm)
- Micro-SIM (15mm x 12mm x 0.76mm)
- Nano-SIM (12.3mm × 8.8mm × 0.67mm)