What is a SIM Card? Solution to the problem coming in SIM slot

What is a SIM Card? Solution to the problem coming in SIM slot What is SIM in this post (what is sim card), what is the full form of sim, and the problem coming in its slot (Connector) like Card not detected, Slot not working in mobile, Insert card error solution and how to install Jumper in SIM IC, and SIM Authentication Process has been told.

What is a SIM Card?

The full form of Sim is the Subscriber identity module . It is a type of chip. Which connects the mobile phone to the network. There is a separate section of SIM in mobile phone. If there is any defect in this section, then many types of problems can be created in the mobile phone.

Different types of SIM – Different sizes of SIM

What is full size sim?

When the first SIMs were launched, they used to be big in size, their size was almost as much as Debit Card. 

What is Mini-SIM?

Their size was about 15 X 25 mm, which is mostly plastic and there is a chip in the middle.

What is Micro-SIM?

Micro sim card is slightly smaller than mini sim card, its size is 12 X 15 mm, it has less plastic around the chip.

What is Nano-SIM?

Nano sim card is the smallest sim card, its size is about 8.8 x 12.3 mm, nowadays most of the phones are fitted with nano sim cards.

 What is e-SIM?

e-SIM is an electronic SIM card, its full name is embedded-SIM. It is pre-installed in the form of a chip in the motherboard of the mobile phone. It does not require a separate SIM slot.

SIM Authentication Process

Whenever you insert a SIM in the phone, it receives the IMSI (International Mobile Subscriber Identity) number from the SIM and sends it to your network provider, then the network provider searches your IMSI number and authentication key in its internal database, and then After a code is generated by combining the authentication key with a random number, then send that random number back to the SIM, and then the SIM card generates a code by combining the code sent by the network provider with its authentication key. and sends it again to the network, if the code generated by the network and the code generated by the SIM match, then the SIM is declared valid. This can be understood with the help of the example given below

Suppose you have inserted a SIM in the phone and that IMSI number is sent to the network and the network searches the IMSI number and authentication key in its database. 

The network then generates a random number “X”, and calculates it with the authentication key to create a new number “Y”, then the network provider sends the “X” to your phone, then the SIM “X”. Generates a new number “Z” by calculating it with its authentication key, then this number (Z) is sent again to the network where Z is matched with Y if Z matches Y So the service of SIM gets activated.

SIM Section

In any mobile phone, a connector is given to insert the SIM, and some components and ICs are installed around it, this section is called SIM section. There are 6 points in the SIM connector-

(1) Data
(2) Clock
(3) Reset
(4) V SIM
(5) Ground
(6) Not Connected

  • SIM Data – This is a digital data that is stored in the memory of the SIM card.
  • SIM Clock (CLK) – This is a clock frequency signal that combines digital data to form a signal to send and receive data information.
  • SIM Reset (RST) – This is also the signal frequency that resets the process.
  • V SIM – This terminal stands for Power Supply Voltage. Which activates the SIM circuit.
  • SIM GND – This is a ground line voltage.
  • NC – This terminal is not connected to anyone.

Types of Sim Card Problem in Mobile

  • Showing of Insert Sim Card error even when SIM is engaged.
  • SIM card not working.
  • Phone can’t Detect SIM Card error Show करना।
  • Sim slot not working
  • Invalid SIM error show करना।
  • SIM Card not Accepted Show करना।

Solution of Problems coming in SIM Card or Slot

  • Check by dialing IMEI Number (*#06#), if any kind of error occurs, then repair IMEI.
  • Clean the SIM section thoroughly and try it.
  • Screech the SIM card tips and the point of the SIM connector.
  • Tracing the SIM section.
  • If a circuit is open then jumper. If it is short then try to remove the shorting or replace it.
  • Tracing from V Sim terminal to Power IC, if Voltage is not coming then check Power IC.
  • Try Resold or Replace Sim Connector.
  • Check CPU.
  • While charging the battery, if the problem of “Not Charging” and SIM card comes together on the display, then check the BSI point of the battery.

Tip- If the SIM IC gets damaged and the IC is not available, then the SIM IC can be removed and jumper can also be done in its place, for this remove the IC carefully with the help of Hot Air Gun, after removing the IC, eight Point appears. In which we can jumper as follows.

Sim Connector in Mobile PCB