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What is Plain old telephone service aka POTS

Plain old telephone service (POTS), or plain ordinary telephone system,[1] is a retronym for voice-grade telephone service employing analog signal transmission over copper loops. POTS was the standard service offering from telephone companies from 1876 until 1988[2] in the United States when the Integrated Services Digital Network (ISDN) Basic Rate Interface (BRI) was introduced, followed by cellular telephone systems, and voice over IP (VoIP). POTS remains the basic form of residential and small business service connection to the telephone network in many parts of the world. 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).

What types of devices rely on analog telephone lines alson known as POTs?

Many systems have been built using POTs line signaling technology and depend on their reliability for their function. Some systems also depend on central office supplied power (48V DC on-hook). Examples of POTs dependent systems include:

Fire Alarms


Call Boxes and dedicated phones for 911 Emergency Services

Point of Sale Systems


Gate Access

Faxing and privacy compliance

Business Resiliency and BCDR (redundancy for other voice transport)

SCADA systems

Out of Band Systems Management

What is POTS? Origins of the Plain Old Telephone Service

POTS or Plain Old Telephone Service is a term that refers to the traditional landline phone system that many of us are familiar with.

Put simply, POTS is an analog voice transmission system that relies on copper twisted pair wires to connect callers. This system originates with the invention of the telephone by Alexander Graham Bell back in 1876, though there have been some upgrades since then.

Originally, the copper telephone lines were suspended overhead on poles or across rooftops. As technology advanced, though, it became more common to bury these lines underground. These traditional copper telephone lines are what we refer to as copper landlines or POTS lines.

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