Plain Old Telephone System -or- Pat On The Shoulder
(pronounced : pots)
The standard telephone service used when making telephone calls. Technically, it is a collection of interconnected systems operated by various telephone companies and administrations around the world. The main distinctions between POTS and non-POTS services are speed and bandwidth. POTS generally delivers about 52 Kbps (52,000 bits per second).
Non-POTS services (such as ISDN) are much quicker and involve features that make them preferable for accessing the Internet. (For example, with ISDN or DSL you can use one line for both voice and data versus having to get a second phone line for your Internet connection.)
The POTS network is also called the Public Switched Telephone Network (PSTN).
It started with human-operated, analogue, circuit-switching systems (called plugboards) and has evolved into electromechanical switches so that the transmission is completely digital-except for the final connection to the subscriber (which is why Internet users are opting for DSL, an always-onconnection with better speed).