Definition
The Public Switched Telephone Network (PSTN) is the traditional, worldwide circuit-switched telephone network. Voice AI platforms bridge internet-based calling to the PSTN so agents can reach ordinary phones.
Why it matters
Connecting to the PSTN is what allows an AI agent to call or receive calls from any standard phone number.
Frequently asked questions
How is PSTN used on a real phone call?
On a live call, PSTN shows up in the moments that decide whether a caller books, waits, or hangs up. It sits in the Telephony layer of the voice stack and works alongside Telephony, VoIP, SIP — evaluate it on real calls with background noise and interruptions before trusting it in production.
Why does PSTN matter for AI voice agents?
Connecting to the PSTN is what allows an AI agent to call or receive calls from any standard phone number. In practice, teams confirm it in the first weeks of Telephony review: when bookings hold and handoffs stay clean, the deployment is earning its keep.
How is PSTN used in AI phone call automation?
In AI phone call automation, PSTN is part of the Telephony foundation. It connects closely to related concepts like Telephony, VoIP, SIP, which together shape how a voice agent understands callers and completes real tasks such as booking appointments and qualifying leads.
Sources
Definitions and claims on this page are grounded in the following authoritative external references.
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