mobile phone experience from functional machine to process intelligent machine evolution happened to turn the world upside down change, but as a communication based on products, no matter how powerful its function, application scenario is how complex, it always cannot do without using SIM to pass through it, or is the user identity data storage mobile network connection. Compared to those who obviously stunt innovation, evolution is not the SIM card is everyone will pay attention to, but it is by virtue of this innovation makes manufacturers low-key constantly improve the industrial design and the internal structure of the intelligent mobile phone.
do you really know the SIM card,
most people for the understanding of the SIM card is actually limited to the surface, only know that the SIM card inserted in the phone can call, internet. Unconsciously, the shape of the SIM card has undergone great changes. What big and small card, standard card said very awkward does not say, even when you buy a new mobile phone before Wu heat on priority to business card fix things, of course, carry on iPad are essential tools.
SIM is the full name of the subscriber identity module card, English named Subscriber Identity Module, the main role is to store the user identification data, text data, telephone number; 2G, 3G, 4G to achieve access network management; user PIN code encryption, etc..
SIM card composed of CPU, ROM, RAM, EEPROM and I/O circuit, when we want to use the SIM card, SIM card mobile phone is actually need to issue a command, then the SIM card according to the local standard specification to perform or reject, it itself is not simply the information storage device.
You also need to know the SIM
card itself is a capacity of the points, including 8KB, 16KB, 32KB, 64KB, 128KB and even 512KB large capacity SIM card, the capacity can be used to store information, telephone or SMS content of operator service.
mobile phone SIM card has four forms of
after the popularity of mobile phones, SIM cards have gone through a total of full size SIM card, mini SIM card, micro card, nano card SIM these four stages, we look at the difference between them.
1, Full SIM size card (original card)
‘s first SIM card and credit card size standard version is similar, which is similar to the IC telephone card, generally used for large communication equipment, this card can indicate SIM card information, such as the number or PUK code, convenient for users to save after purchase.
2, mini SIM card (standard card)
taking into account the miniaturization of smart phones, since the beginning of 91 years, SIM card gradually become mi>