There are two kinds of "calling" phones: person-to-person and machine-to-machine. Developers generally require "casting a wide net". Because of the huge number of calls to be made, "callers" often choose machine to machine. "Calling" doesn't need to get your phone number, just get the number field of a region and dial it one by one. For example, "1390574" belongs to Ningbo, that is, "13905740000" to "9999" all belong to Ningbo.
Extended data
Harassing phone calls not only disturb personal life, but sometimes their accurate personal information also raises people's concerns about privacy disclosure. Xue Xue, who once worked in the sales departments of two real estate companies, said that as long as consumers leave their phone numbers in real estate companies, they will be pulled into the "resource pool". Not only will real estate companies share each other, but even "traffickers" will openly buy and sell, and even the outlets of telecom operators will participate. Behind the harassing phone call is actually the naked sale of personal information.
Yu Dandan, a lawyer of Dacheng Law Firm, said that personal telephone information is a part of personal privacy, and it is illegal for anyone to sell telephone information for profit. However, there are no laws and regulations to punish harassing calls in China, and it is difficult to obtain evidence and investigate in specific judicial operations, so harassing calls are condoned as a marketing method.
References:
Public trust. Com _ Revealing the interest chain behind harassing phone calls: professional phone customers cast nets to promote sales.
References:
The developer of China Economic Net _ Telephone Explosion Emergency Center was accused of being behind the scenes.