F.C.C. Warns About the ‘One Ring’ Robocall Scheme https://nyti.ms/2J2fOkH

In the scheme, the phone rings once with no message, prompting some consumers to call back and be connected to a high-billing number, similar to a 900 one.
The New York Times U.S. Frauds and Swindling, Telemarketing, Telephones and Telecommunications
By SANDRA E. GARCIA from NYT U.S.
https://nyti.ms/2J2fOkH