22/12/2021
What is a SIM Card?
SIM stands for Subscriber Identity Module. It is one of the most important part of any mobile phone. In some countries it is also known as ICC (Integrated Circuit Card) and UICC (Universal Integrated Circuit Card).
In simple terms, a SIM Card is basically a microcontroller-based access module or a small portable memory chip that stores information about the mobile phone user, a 16-digit or 17-digit code to identify its country of origin, network carrier information and a unique user ID / Mobile Phone Number.
DIFFERENT SIZES OF SIM CARD
SIM Cards are available in 3 basic sizes: Standard, Micro, and Nano.
Out of these three sizes, the Standard Size is the original. Micro and Nano SIM Cards were made smaller by trimming off the extra plastic around the main circuit.
TYPES OF SIM CARD
SIM Cards are of mainly 3 Types
(i)GSM SIM Cards
(ii)CDMA SIM Cards
(iii)e-SIM Cards
GSM SIM cards
GSM stands for Global System for Mobiles. It can be removed and inserted in any mobile cell phone.
CDMA SIM cards
CDMA stands for Code Division Multiple Access. It cannot be removed from the original Phone.
eSIM Cards
Nowadays there is a new Mobile Phone Communication Technology called eSIM Card. eSIM stands for Embedded SIM. There are no physical Chip involved. A small chip is pre-assembled inside the phone and works in a similar way to the NFC chip. You can also port / swap your Network Operator because the information on eSIM is re-writable.
SIM CARD PARTS AND FUNCTION
Different Parts of Circuit on a SIM Card have different Function. Following are the Major Parts of a SIM.
VCC (Power Supply)
RST (Reset)
CLK (Clock)
D+ and D- (Optional USB Pad)
GND (Ground)
VPP (Voltage Programming Power)
SIM Data I/O Pin