What Is SIM Card, Full Form Of SIM Card

A Subscriber Identity Module (SIM) card is a chip inside most modern cellular phones that stores information your phone needs to communicate with your carrier’s cell towers. SIM cards come in different sizes and if you were to remove the SIM card from your phone you wouldn’t be able to text, call, or access anything on the internet.

What Is A SIM Card?

Believe it or not, SIM cards have been on the scene since 1991. They were first developed by a German manufacturer for a Finnish mobile carrier. Billions of SIM cards have been sold to date.

SIM cards are mandatory for phones connecting to the Global System for Mobile communications (GSM) networks, which is the telecommunications standard in over 193 countries that stores identification and security data on the card.

A SIM card is a small smart card made up of embedded contacts and semiconductors that has gone through four sizes over the years:

Full-Size (1FF or 1st Form Factor) was the size of a credit card; 85.6 mm x 53.98 mm.

Mini-SIM (2FF) was drastically smaller coming in at 25 mm x 15 mm first being used in 1996.

Micro-SIM (3FF) made improvements in length with measurements of 15 mm x 12 mm.

Nano-SIM (4FF) is the most recent form and is 12.3 mm x 8.8 mm.

As phones got smaller and thinner, the need for smaller components inside became more apparent. Having a card the size of a credit card inside a device the same size wasn’t realistic. Nowadays, SIM cards have been stripped down, removing almost all the surrounding plastic, and are essentially just a small chip.