What is the nail card for?

Alibaba's communication office software has launched an exclusive mobile phone card-"Nail Card". Like the special mobile phone cards launched by internet companies before, they are all sold through the corresponding preferential ways of APP free traffic+monthly large traffic, with the ultimate goal of expanding the user base and activity of APP.

Mobile phone card: also known as subscriber identification card and smart card, GSM digital mobile phone can only use this card. Digital mobile phone customer information, encryption key and user phone book are stored on the computer chip, which can be used to authenticate the identity of GSM network customers and encrypt the voice information when customers talk.

SIM card is mainly used in GSM network, W-CDMA network and TD-SCDMA network, but the compatible module can also be used in IDEN mobile phone. Some people refer to the RUIM card and UIM card of CDMA2000 and cdmaOne, also called SIM card. Although they have similar functions and abide by all the same mechanical and electrical standards and some software standards, the upper applications are not necessarily compatible.

SIM card consists of CPU, ROM, RAM, EEPROM and I/O circuit. When users use SIM, in fact, the mobile phone sends commands to the SIM card, and the SIM card should be executed or rejected according to the standard specification; SIM card is not a simple information memory.

In 20 18, China Unicom officially took the lead in handling the "eSIM-1 dual terminal" service in six cities: Shanghai, Tianjin, Guangzhou, Shenzhen, Zhengzhou and Changsha. "esione multi-terminal" means that wearable devices can share numbers with users' mobile phones without a physical SIM card.

SIM card Baidu encyclopedia