Telnyx AI Voice Agents can now register as SIP endpoints on existing enterprise voice systems. With SIP Attach, teams can add an AI agent to a PBX, softswitch, or unified communications platform, then route calls to it through the dial plan, queues, and internal extensions they already operate.
SIP Attach is different from SIP trunking. Instead of using Telnyx as the trunk for the PBX, the Telnyx Voice AI Agent registers to the customer's PBX, softswitch, or UC system as a SIP endpoint, similar to an internal extension.
Enterprise voice teams already have routing systems they trust. Extensions, queues, permissions, failover behavior, access rules, and call handling logic usually live inside a PBX, softswitch, or unified communications platform.
Before SIP Attach, adding an AI agent to those workflows often meant creating an indirect path to reach the agent. Teams could assign a phone number, build forwarding logic, or coordinate SIP URI routing between systems. Those approaches can work, but they move the integration burden into routing glue: domains, access rules, dial plan changes, firewall behavior, and interop testing.
SIP Attach changes the model. The AI agent registers as a SIP endpoint inside the customer's voice system, so the existing routing layer can treat it like another reachable destination. Internal users dial the extension, queue, or call path they already know. Telnyx runs the agent conversation once the call arrives.
Learn more in the UAC connection support guide.
