--- "@context": https://schema.org "@type": TechArticle "@id": https://www.twilio.com/docs/glossary/what-is-pstn#article headline: What is the PSTN (Public Switched Telephone Network)? description: The PSTN (Publicly Switched Telephone Network) is the network that carries your voice calls when you call from a landline or cell phone. It refers to the worldwide network of voice-carrying telephone infrastructure, including privately-owned and government-owned infrastructure. url: https://www.twilio.com/docs/glossary/what-is-pstn inLanguage: en dateModified: 2026-08-13T17:05:12.000Z author: "@type": Organization name: Twilio Developer Education Team publisher: "@type": Organization name: Twilio --- # What is the PSTN (Public Switched Telephone Network)? The PSTN (Publicly Switched Telephone Network) is the network that carries your voice calls when you call from a landline or cell phone. It refers to the worldwide network of voice-carrying telephone infrastructure, including privately-owned and government-owned infrastructure. Interfacing between the internet and the PSTN has traditionally been costly and difficult. The Twilio Programmable [Voice API](https://www.twilio.com/en-us/voice) abstracts this complexity away, giving developers verbs like [\](/docs/voice/twiml/dial) and [\](/docs/voice/twiml/conference) to execute voice calling tasks that were difficult in the past.