PSTN, or Public Switched Telephone Network, is the world's collection of interconnected voice-oriented public telephone networks, both commercially operated and government-owned. It's also referred to as the Plain Old Telephone Service (POTS).
PSTN is used globally to provide telephone service to households, businesses, and government entities. It covers telephony in a broad sense, including the conveyance of voice, fax and dial-up internet services.
PSTN and VoIP both serve the same purpose of enabling communication but they differ in their method of transmission. PSTN uses circuit-switched telephony while VoIP uses packet-switched telephony.
PSTN uses circuit-switching technology. When a call is made, circuits are switched in the intervening telephone exchange to connect the call.
Some related software includes VoIP services like Skype and Google Voice, which provide an alternative to traditional PSTN lines.
PSTN is reliable and has a wide coverage. It also provides high-quality voice transmission and is easy to use and understand.
PSTN has been the backbone of global communication for many years. Despite the emergence of newer technologies like VoIP, PSTN still holds relevance due to its reliability and widespread use.