Using telephony (SIP-Voicebot)
How telephony is built, what you can configure yourself — and what is done exclusively by Zentor.
Last verified: 2026-07-24
Telephony does not run inside Zentor itself but in a separate SIP solution (Asterisk with PJSIP and ARI) that is decoupled from the chatbot. Every tenant gets its own isolated SIP instance there — there is no shared process and no shared line between tenants. Zentor is the control and display layer: Zentor issues call orders, supplies knowledge and limits, and displays results. The conversation itself — speech recognition, knowledge retrieval, answer generation, and speech output — is carried out by the SIP instance on its own. Telephony is a separately bookable add-on and is not unlocked automatically with any package.
Step by step
- Have the add-on bookedIf telephony is not booked for your tenant, the "Phone bot / SIP" page shows a corresponding notice. Booking happens through Zentor. Without the add-on, call orders are blocked and no usage data is shown.
- Enter your phone numberAfter booking, enter and save your phone number (DID) in the "Phone bot / SIP" section. There is no longer any provider or technology selection here — the technical connection lives entirely in the separate SIP solution.
- Wait for activation by ZentorProvisioning the isolated SIP instance as well as activation and deactivation are done exclusively by Zentor; the UI states this explicitly. There is deliberately no self-service button.
- Keep an eye on minute costs and limitThe "Minute costs" section shows spend, limit, minutes, and number of calls for the current billing period. Once the cost limit is reached, new calls are blocked.
- Trigger a test callWhen your telephony is active, you can enter a number and order a call. Zentor hands the order to your SIP instance; Zentor itself never establishes a connection. Ongoing calls can be ended from the call log.
- Review the call logThe call log shows direction, numbers involved, status, duration, cost, and date per call. These entries are purely a mirror of the results your SIP instance reports back to Zentor after a call ends.
Expected result
Your phone number is stored, Zentor has passed the order, knowledge, and limits to your isolated SIP instance, and status, result, duration, and cost of every call flow back into your call log via the instance's result reports.
Common error cases
I cannot activate telephony myself.
Cause: This is intentional — activation and deactivation are reserved exclusively for Zentor, regardless of whether the number and configuration are already stored.
Resolution: Contact Zentor once your configuration is ready.
A call order fails saying no telephony instance exists or is connected.
Cause: No isolated SIP instance has been provisioned for your tenant yet, or it is not yet linked to a reachable interface.
Resolution: This is a provisioning step on the Zentor side. Contact Zentor — nothing needs to change in your configuration.
New calls are rejected even though telephony is active.
Cause: The cost limit for the current billing period has been reached.
Resolution: Check the "Minute costs" section. To raise the limit, contact Zentor.
I want to hand calls over "warm" to an employee (transfer during an ongoing call).
Cause: A warm transfer during an ongoing call is not available at this time.
Resolution: Discuss your requirement with Zentor; for chat, handover to an employee is available independently of this.
I can no longer find the provider selection or the simulation notice described earlier.
Cause: The former telephony bridge embedded in Zentor was removed completely; the technology now lives in the separate SIP solution.
Resolution: This is the intended current state — number, costs, and call log stay in Zentor, everything technical sits with your SIP instance.