Public switched telephone network is the aggregate or the collection of global interconnected voice-based telephone networks that are owned, operated, and managed by several regional, national, global, or jurisdictional telephony operators. The prime function of PSTN is to provide efficient infrastructure and services required for public telecommunication. Ideally, a public switched telephone network consists of cellular networks, telephone lines, microwave transmission links, fiber optic cables, undersea cables, all the switching centers, and even communication satellites, and all these allow telephones to efficiently communicate with each other.
Earlier, public switched telephone network was a network of fixed-line telephone system and analog telephone system. However, over the course of time, it became entirely digital, and because of the digitization of its core network, it has successfully been able to integrate mobile networks and fixed telephone into one platform. This has certainly enabled telephony operators expand their area of expertise, and respond to dynamic networking requirements in the most competent manner. PSTN allows access to telephone assistance and services at much affordable price. Not only this ensured provisioning of telephone-based call center services to people at minimum cost, but also paved way for efficient integration of multiple communication channels in one platform.
The policies regarding technical operation of PSTN are formulated and implemented based on the standards created by International Telecommunication Union (ITU). These standards basically allow different network across varied geographical realms to connect with each other seamlessly. The standard also specifies single global address space for telephone numbers across countries. The combination of public switched telephone network, single numbering plan, and interconnected networks allow efficient telecommunication system across the globe. The task of setting up an intact telephone network was earlier considered to be the responsibility of network operators; however, as this required huge investment and provision of telephone assistance and services became a crucial public utility, it was important for government to take relevant initiatives. Therefore, in most of the countries, the central government dedicates special regulatory body to monitor the provision of PSTN services in the most comprehensive and immaculate manner.