The Public Switched Telephone Network (PSTN) refers to infrastructure that supports switched telephone connections (dial service) between telephone endpoints as defined by the ITU-T, and operated telephone carriers.
The PSTN is actually a network of networks operated by local , national and international telephone carriers. The term originally referred to voice-grade telephone service employing analogue signal transmission over copper twisted pair and electro-mechanical switched-circuit telephone exchanges.
Over the years, carriers have been replacing analogue signalling and mechanical switches with digital signalling and switching. ISDN, cellular phones, VoIP, are all part of the PSTN, as they are circuit-switched services although more frequently they are being backboned on the TCP/IT (packet switched) network infrastructure.
Created 2023-03-09 05:08 by Stephen B (Revised 2023-03-09 05:36)