POTS is telephone service that employs analog signal transmission over copper loops, that exists in many buildings. A standard technology over most of the 20th century, POTS is being replaced by newer technologies such as integrated services digital networks (ISDN), voice over IP (VoIP), and cellular networks from carriers such as T-Mobile.
The Federal Communications Commission (FCC) tightly regulated POTS through the 1990’s. Now, in the 2019 FCC 19-72 order effective August 2022, they have lifted its oversight and no longer see any reason to require Carriers to continue POTS service.