Plain old telephone service (POTS) is the voice-grade telephone service that is based on an analog signal transmission that was common before the advent of advanced forms of telephony that most homes use.
The term reflects the technology that has been available since the introduction of the public telephone system in the late 19th century, in a form mostly unchanged despite the introduction of Touch-Tone dialing, electronic telephone exchanges and fiber-optic communication into the public switched telephone network (PSTN).
Considered a standard land-line, it consists of a twisted-pair of copper wires and is a dial-up telephone service provided to homes and business for basic communications, without any features such as call waiting, call forwarding, caller ID, etc. From the telephone company’s point of presence (POP) up to the customer’s telephone exchange it is an analog service (with a bandwidth of 56-64 kilobits per second or kbps). The main distinctions between POTS and non-POTS services are speed and bandwidth. The POTS network is also called the public switched telephone network (PSTN).