Disguised mobile phone displaying sim card signal

The developer option has a demo machine setting, which some old models don't.

There is a technology called virtual SIM card. For example, Xiaomi's Mi SIM (one yuan traffic, global Internet access), Nokia's international traffic, and the eSIM promoted by Apple in conjunction with mainstream operators around the world. Another strategy is called card scrapping. Just insert an invalid SIM card.

SIM card (subscriber identity module) is a smart card held by mobile users in GSM system, which can be used on different mobile phones, also known as subscriber identity card. SIM card is mainly used to store user identification data, short message data and telephone number. GSM mobile phones can only use this card. Once the SIM card is unplugged from the mobile phone, the mobile phone will not be able to enjoy all kinds of services provided by network operators except emergency calls. 20021May 12, the Ministry of Industry and Information Technology held a video conference in Beijing to prevent and control telecommunication network fraud, strengthen the risk remediation of key businesses such as telephone cards and Internet of Things cards, and accurately rectify the illegal transactions of "telephone cards and Internet of Things cards".