Communication service is not like buying things and tickets. If you buy it, you will spend money; if you don't buy it, you will not spend money. Communication service means that as long as you get a card, you have already started to use the communication service, instead of not using it without calling. Therefore, the cost of communication infrastructure in the whole country is shared by users all over the country through monthly rent. The communication base station will communicate with your card every once in a while, so as to determine your location and be able to contact you when there is a phone call, text message, etc. It's just that the current charging method is calling charge, and the called party doesn't charge.