POTS Definition

POTS is an acronym for plain old telephone service, which refers to the standard low speed, analog telephone service that is still used by most homes and many businesses.

The term is sometimes used to distinguish that service from the newer telecommunications services which are digital and have much larger bandwidths. These include ADSL (asymmetric digital subscriber line), ISDN (integrated services digital network) and FDDI (fiber distributed data interface).

The newer services provide some part of their channels for POTS while using most of their bandwidth for digital data transmission. The newer services also make possible added features such as call waiting or call forwarding.

POTS utilizes the lowest 4kHz of bandwidth on twisted pair wiring (i.e., conventional low-speed copper wiring). Any service sharing a line with POTS (e.g., DSL) must either use frequencies above POTS or convert POTS to digital signals and interleave them with other data signals.

Users accessing the Internet with the same twisted pair copper wiring as is used by their telephone are using a POTS connection. The TCP/IP (transmission control protocol/Internet protocol) digital data from their computer or LAN (local area network) is converted to analog format using a modem prior to transmission over the POTS.

POTS is sometimes used as a synonym for PSTN (public switched telephone network). However, the latter usually has a broader meaning: it refers to the worldwide collection of interconnected public telephone networks that were designed primarily for voice traffic but which now use high speed digital links for nearly all of their trunk and intermediate lines and which are carrying an increasingly large share of non-voice traffic.

POTS should not be confused with pot, an abbreviation of potentiometer (i.e., a variable resistor).

Created October 18, 2005.
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