Source: Federal Communications Commission (FCC)
May 6, 2019 (Washington D.C.) -- For illegal robocallers, the goal isn't always getting you to answer. Sometimes, it's getting you to call back.
Every so often, your phone may ring once and then stop. If that happens to you, and you do not recognize the number, do not return the call. You may be the target of a "one-ring" phone scam.