PSTN

telephone system based upon copper wires that carry analog voice signals

The public switched telephone network (PSTN) is the network of the world's public circuit-switched telephone networks, in much the same way that the Internet is the network of the world's public IP-based packet-switched networks. Originally a network of fixed-line analog telephone systems, the PSTN is now almost entirely digital, and now includes mobile as well as fixed telephones. It is sometimes referred to as the Plain Old Telephone Service (POTS).
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Abbreviation for public switched telephone network.

A domestic telecommunications network usually accessed by telephones, key telephone systems, private branch exchange trunks, and data arrangements. Note: Completion of the circuit between the call originator and call receiver in a PSTN requires network signaling in the form of dial pulses or multifrequency tones.

Public Switched Telephone Network

Public Switched Telephone Network

Context: Infotech