telephone services

Plain old telephone service, or POTS, is the standard, analog telephone service that remains the basic form of residental and small business telephone service nearly everywhere in the world, and was the only basic telephone service known to most people until the introduction of mobile phones. It has been available almost since the introduction of the telephone system in the late 19th century, mostly unchanged to the normal user since then despite the introduction of electronic telephone exchanges into the public switched telephone network since the middle of the 20th century.

The system was originally known as the Post Office Telephone Service or Post Office Telephone System in many countries. The term was dropped as telephone services were removed from the control of national post offices.

POTS services include:

With the advent of electronic telephone exchanges and computerisation during the 1970s and 1980s, a raft of new network services became available. These had been termed PANS for pretty advanced network (or new) services by some in the industry, although that term has never really caught on. BellSouth.