SIM card has gone through many style changes since its emergence, from the original card the size of a bank card, to the commonly used Nano Sim card, to the unpopular eSIM card .
SIM card style
With the advancement of mobile phone manufacturing technology, the popularity of Apple mobile phones, and the alignment of domestic mobile phones, as well as for the sake of standardization and simplicity of manufacturing, more and more operators and mobile phone manufacturers have adopted Nano Sim cards.
Common SIM card styles
Now, when you apply for a mobile phone number, the card you use to open the card is much smaller than before, about half the size of before.
Radio and television card board style
The current card board with one card for three purposes and multiple cards in one is under the impression that it was manufactured by and Xiaomi . This simple choice of three makes China's four major operators extremely happy. Salespersons no longer need to use card cutter to cut cards, and the probability of SIM card damage is greatly reduced.
It can also be seen from this card board of China Radio and Television that no matter what kind of SIM card it is, the metal part has the same style, and the only change is the area of the plastic.
What is the location of the small metal piece in the SIM card? Please look at the picture below:
The reverse side of the SIM card after disassembly
The front side of NANO SIM
As can be seen from the front view, the I/O contact closest to the beveled corner of the NANO SIM card is the I/O contact, the VPP contact is above it, and the VPP contact is above it. GND contact; from bottom to top on the left are the CLOCK contact, RESET contact and VCC contact. Explanation of the purpose of the
contacts: power supply VCC, used for SIM card power supply; reset RESET, used to reset the SIM card processor, etc.; clock CLOCK, used for time calibration reference; ground terminal GND, ground wire negative terminal, used for Circuit insurance; programming voltage VPP, usually empty; data I/O port, used for data transmission.
As you can see from the picture on the back, the middle position of the SIM card contains CPU ( central processing unit ), RAM (working memory), ROM (program memory), EPROM or EEPROM (data memory) and serial communication unit etc. 5 module integrated circuits. The five small dots on the metal sheet of the SIM card are the lead soldering points where the contacts are connected to the integrated circuit.
花家丁卯Rabbit
Who would have thought that a NANO SIM card with a thickness of about 0.7 mm and an area as big as a fingernail can integrate so many functions.
eSIM cards are not yet popular in China. Except for portable terminals such as phones, watches, and the Internet of Things, they have not been effectively used on mobile phones. In the 5G era, everything is connected. It is hoped that eSIM cards can be used in mobile phones earlier to bring mobile phone manufacturing to a higher level.
