• History Of Sim Card:
In the late 1960s, a smart card was introduced. This smart card was based on a silicon integrated circuit chip. This smart card is considered as flash memory and EEPROM ( Electrically erasable program read-only memory) in which electrical rays are used to remove or change any data which is stored in the chip. In the starting, this smart card was specifically for European Telecommunications Standards Institute. They gave it a specific number TS 11.11. This number is specified to give information about the logical and physical properties and behavior of SIM cards. The first sim card was made by Munich smart-card maker in 1991. They sold 300 sim cards at the very starting and initial point.
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Sim card stands for Subscriber Identification Module. It is an integrated form of circuit.Sim cards can store a large number of data like contact numbers and information.Every sim card contains a different number than any other sim card. The sim user has access to two different types of security passwords:
- PIN (personal identification number) for common use.
- PUK (personal unblocking key) for pin unlocking.
• Operating System:
- There are voltages required to operate the sim card. These voltages are 3V, 5V, 1.8V which are further divided into classes like Class A, Class B, Class C respectively. These voltages for operating were launched before 1998 for most of the sim cards was 5V. Then after some time, the sim card produced the voltages 3V and 5V. And now in the present age, there are three types of voltages use most commonly which are 5V, 3V, and 1.8V.
- In the present modern age, sim cards permit many applications to load when the sim is in the of the subscriber.
• Data Storage:
Data can also be store in sim cards. Most data is stored in network-specific information. Data is also stored to authenticate and for the recognition of any contact or the identity of any other network. It can store a large number of data ranges from 8 KB to 256 KB.It is the identifier for the chip of SIM cards.
• Identification Number:
- There is a specific country code provided to every sim card. This code is specific for every country and can not be changed in any situation. For example, Canada uses 302 as her country code which can not be changed.
IMSI stands for International Mobile Subscriber Identity. The operators of mobile networks do connect mobile phone calls and do communicate with their market SIM using their IMSI number.
- The first three digits of this format represent the country code.
- The next represents the MNC code which depends on the next two or three digits.
- By following the rule of MSI there should be always less than 15 digits of a sim card. No sim card should be more than 15 digits, this will violate the rule.
• Identity Of Location:
The location area identity is used to find the state of network information which is stored. The operator networks are divided into many regions and these regions are having their own number of location area identities.
• Messages and contacts:
Sim cards store several messages and contacts in them. The storage of these messages and contacts in the sim card depends upon the storage capacity of the sim. The early products are having the capacity to store only 5 messages and 20 contacts only. Whereas, the modern sim cards have the capacity to store more than 200 contacts i.e. almost 250 contacts.
• Size Of Sim Cards:
There are different sizes of sim cards available at present. These include full-size sim cards, mini-sim cards, micro-sim cards, and Nano-sized sim cards available.
- The first sim card introduced was equal to the size of the credit card. Later, there are small-sized sim cards that are introduced which are smaller in size.
- The next sim card was mini sim cards which were almost 18 mm and did not have a plastic backing plate in them. These mini sim cards were having the same functions as the full-sized sim card had.
- The third one is micro sim cards which have the same thickness but there is a reduction in the length and width of the sim card.
- This is the latest form of SIM cards which is present today also. It has a very small size
In 2019, it seemed in research thatmany people spreadd the vulnerabilities in some sim cards by finding their location. They start finding locations and then hack the mobile phones and all the data which is present in the mobile phone. Strict action is taken by the sim security in the year 2019 and it seemed in many types of research that the problems of security have almost been solved.
• Usage Of Sim Cards:
Sim cards are used in GSM devices. Sim cards are most commonly used in mobile phones to save contacts, for messaging, and to communicate with any person. Mobile phones are worthless without sim cards. Sim cards are essential for local calls, text messages, and the usage of the internet also. In the present time, almost every person has a mobile phone and there is a sim card also present inside it.
Sim cards had become as important for the mobile phone from the very first day when the mobile phone had invented. Mobile phones are worthless without sim cards. It is a basic need. One can call his loved ones, can send text messages, and also can use the internet . In the present age, every person has a mobile phone and also there is a sim present on every mobile phone. So, No one can deny the importance of sim cards.