Call flow
- A caller dials a number linked to a Zendesk account.
- Zendesk uses the Overflow feature to redirect the call to PolyAI. This requires a phone number from a SIP provider such as Twilio or Gamma.
- Twilio converts the PSTN call to SIP and sends it to PolyAI.
- PolyAI initiates a SIP INVITE to an outbound integration, routing the call to a SIP URI provided by Zendesk.
- Zendesk agents receive the call. If a ticket exists, they see its ID with the
X-Zendesk-Ticket-IdSIP header.
Setup
Configure PSTN forwarding
Zendesk numbers route calls internally by default. To send calls to PolyAI, enable Overflow.- Create an empty agent group in Zendesk Talk.
- Set the inbound number to route only to this group.
- Configure Overflow to forward calls:
- If no agents are available (the group is empty, so this is always the case).
- Outside business hours.
- Disable voicemail for this number.
Enable SIP in Zendesk
Zendesk requires SIP to send calls to external systems.- In Zendesk, go to Admin Center.
- Select Channels → Talk → Lines.
- Click Add Line → Add SIP Line.
- Register a SIP address. Name it to match the client or project.
- Add Kamailio’s IP address range to allow traffic from PolyAI.
Create the outbound integration
Once PSTN forwarding and SIP are configured, contact your PolyAI account manager to set up the outbound integration. PolyAI will configure the SIP routing to connect your Zendesk environment.Handoff using the outbound integration
Once the SIP address is set up and verified, PolyAI can hand off calls to Zendesk agents.For detailed handoff configuration, see Call handoffs. Your PolyAI representative can help with Zendesk-specific routing requirements.