-Technology of a SIM card
SIM card is produced mainly for mobile tele communication.
It is also a member of smart card family but it is not as same as a smart card.
The long form of “SIM” is “Subscriber Identification
Module.” Sometimes, it is known as “Digital Cellular.” The pattern of SIM
contact pad is as same as those of smart cards.
A SIM card is constructed with a simple technology. For main
functions and data storage, it contains 32KB and can be note 50 to 100
telephone numbers. Moreover, the most important thing is that it contains a
powerful radio frequency system for phone callings and messaging.
The life of a SIM card is the ID code that is automatically
signed on SIM card by its operation centre. For a SIM card with a telephone
number, there is a new ID code. Different ID codes are noted on different SIM
cards. And too, ID is safety protected. However, SIM cards can be cloned by
specialized SIM card readers.
For users, there are PIN code and PUK code for controlling.
If a user modifies a code and forget, the SIM card can be unlocked only in its
operation centre. If user enters wrong PUK code for many times, the SIM will be
locked if it exceeds its limited times.
There are three sizes of SIM cards namely, normal (standard) SIM, micro
SIM and nano SIM. Nano SIM is the smallest size and normal SIM is the biggest
size of SIM cards.
SIM cards are difficult to corrode depending on the quality
of SIM. Nowadays, old SIM cards can be
trade with new SIM cards at its service centre. In order to test a SIM card is
work or not work, it can be tested on another phone. Sometimes, it’s seems that
the SIM card is not work but you may also check your phone SIM card reader is
still work!
**Thank for reading**
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