SIP Trunking Overview
SIP trunking lets you connect external voice systems to Callr using the SIP protocol (Session Initiation Protocol). With SIP trunking, you can send and receive calls between Callr and your own telephony infrastructure such as PBXs, call centers, SBCs, carriers, or real-time voice AI agents.
What is SIP trunking?
A SIP trunk is a voice connection between two systems over IP using:
- SIP signaling (call setup, routing, teardown)
- RTP media (audio stream)
It is commonly used to connect PBXs, call centers, carriers, and AI voice systems.
What SIP trunking enables with Callr
With Callr, SIP trunking lets you connect your own telephony infrastructure to:
- Callr phone numbers (DIDs)
- Callr Actions (call flows)
- Callr APIs
- Callr AI features (transcription, summaries, data extraction)
You can:
- Receive calls from external systems into Callr
- Send calls from Callr to SIP endpoints
- Route calls between AI, call flows, and live agents
- Centralize tracking and analytics
Common use cases
Use Callr for routing, tracking, or AI while agents stay on your existing platform.
Keep your infrastructure and use Callr as a programmable voice layer.
Dial SIP URIs, transfer calls, or integrate conferencing and voice platforms.
Route calls to real-time AI agents and transfer to humans when needed.
Inbound vs outbound SIP
An external system sends calls to Callr for routing, tracking, or AI processing.
Callr sends calls to your PBX, call center, or AI system
When to use SIP trunking
Use SIP trunking if you:
- Already have SIP infrastructure
- Need advanced interoperability
- Want to connect Callr with call centers or AI voice systems
If you only need basic PSTN dialing and tracking, SIP trunking may not be required.
Updated 6 days ago