PSTN

The Public Switched Telephone Network (PSTN) is the global infrastructure of interconnected telephone networks — operated by national and regional telecommunications carriers — that enables traditional telephone calls between any two phones on earth. Despite widespread adoption of VoIP and internet-based communication, the PSTN remains the primary channel through which enterprise contact centres receive inbound customer calls. For AI voice deployments, PSTN connectivity is delivered via SIP trunks or legacy circuits connecting to the enterprise's telephony infrastructure, which routes calls to the Voice Gateway and AI Agent systems.

For enterprise teams, the PSTN matters because real-world outcomes depend on how the capability is integrated, governed, and measured — not just on the underlying technology. For AI voice deployments, PSTN connectivity is delivered via SIP trunks or legacy circuits connecting to the enterprise's telephony infrastructure, which routes calls to the Voice Gateway and AI Agent systems.

Key Points

• Global circuit-switched telephone network — the infrastructure of traditional phone calls
• Remains the primary inbound channel for most enterprise contact centres globally
• Connected to AI voice systems via SIP trunks or legacy ISDN/PRI circuits
• PSTN connectivity is a prerequisite for any AI voice automation deployment
• NiCE Cognigy Voice Gateway connects to the PSTN via all standard telephony interfaces