The Public Switched Telephone Network (PSTN) is a global network of interconnected voice-oriented public telephone networks. It allows users to make and receive calls using traditional landline telephones. The PSTN operates through a series of switches that connect calls, ensuring that voice signals can travel over long distances. PSTN technology has evolved over time, transitioning from analog systems to digital formats. It includes various components such as circuit switching, which establishes a dedicated communication path for each call. Despite the rise of mobile phones and internet-based communication, the PSTN remains a vital part of global telecommunications infrastructure.