The Public Switched Telephone Network (PSTN), also known as POTS (Plain Old Telephone System), is used for the landline telephone system. PSTN was created primarily for analog voice communications over cables that spanned countries and continents and was an improvement over Alexander Graham Bell's basic telephone system. It brought better management and helped turn telephone communications into a lucrative and revolutionary industry.
PSTN – Public Switched Telephone Network
Mobile telephony is the first alternative to PSTN for voice communication. It offers a solution to the impossibility of making and receiving calls with PSTN without a physical connection to a fixed line.
Until recently, PSTN was the standard for most people. Most homes and businesses had landlines. In addition, PSTN was the primary provider for internet connectivity in some parts of the world. Even with the use of alternative communications such as VoIP and other OTT technologies, a PSTN line was often required for internet connectivity.
However, all this has changed. Most people now have a mobile phone and internet access is no longer analogue in most areas.