> ## Documentation Index > Fetch the complete documentation index at: https://docs.20x.business/llms.txt > Use this file to discover all available pages before exploring further. # Call Tab > Call termination, silence timeout, telephony providers, and caller ID configuration The **Call Tab** in Agent Studio controls call lifecycle limits, silence detection, telephony routing, and caller identification for voice interactions. *** ## Overview | Field | Description | | ------------------------- | ------------------------------------------------------------------------------------- | | **Max Call Duration** | Maximum call duration, what happens when the limit is reached, and allowed range/unit | | **Silence Timeout** | What counts as silence, when the timer starts, and what happens after timeout | | **Telephony Provider** | Supported providers (Twilio, Plivo, Acefone) and how to configure/select them | | **Caller ID** | Purpose, source of the number, requirements, and outbound-call behavior | | **Integrations** | How telephony credentials and phone numbers are connected to the agent | | **Configuration Example** | Example of a complete Call Tab configuration and expected call behavior | *** ## Max Call Duration * **Maximum call duration:** Sets the maximum allowable runtime for any single call session handled by the agent. * **Allowed range and unit:** Specified in **seconds** (e.g., `90` for 1.5 minutes, `300` for 5 minutes, `1800` for 30 minutes). Supported range is `10` to `3600` seconds (up to 60 minutes). * **What happens when the limit is reached:** When the active call duration reaches this limit, the platform automatically and gracefully terminates the call. * **Why it matters:** Protects against runaway calls, infinite loops, and unexpected billing charges from dropped caller connections. *** ## Silence Timeout * **What counts as silence:** Any period during a call where the Voice Activity Detection (VAD) engine detects no human speech input. Ambient background noise is automatically filtered out. * **When the timer starts:** The silence timer starts (and resets) immediately after the agent finishes speaking and is waiting for a response from the caller, or during pauses between caller conversational turns. * **What happens after timeout:** If the caller remains silent for longer than the configured timeout, the agent automatically ends the call session to free the telephony channel. * **Allowed range and unit:** Configured in **seconds** (supported range: `5` to `60` seconds; default is `10` seconds). *** ## Telephony Provider * **Supported providers:** * **Twilio** — Global carrier connectivity and high reliability. * **Plivo** — Cost-effective voice routing, especially for India and APAC destinations. * **Acefone** — Enterprise cloud telephony and virtual PBX routing. * **How to configure and select:** * **Tenant Default:** Automatically inherits the default telephony provider configured in your organization's [Integrations](/features/integrations). * **Explicit Selection:** Choose a specific provider from the dropdown to route calls for this particular agent through a dedicated account. *** ## Caller ID * **Purpose:** The phone number presented as the caller identity (CLI) on the recipient's phone screen during outbound calls and automated campaigns. * **Source of the number:** Sourced from verified numbers purchased or registered under the [Phone Numbers](/guides/numbers/purchase-phone-numbers) section. * **Requirements:** * Must be a valid phone number in standard E.164 format (e.g., `+14155552671` or `+919876543210`). * Must be verified or owned under your connected telephony carrier account (see [Caller ID Verification](/guides/numbers/caller-id-verification)). * **Outbound-call behavior:** The carrier transmits this number in SIP signaling headers, displaying it to the callee. Inbound calls returning to this number route directly to the assigned agent. *** ## Integrations How telephony credentials and phone numbers are connected to the agent: Go to **Integrations** in the dashboard and add your telephony credentials (e.g., Twilio Account SID and Auth Token, or Plivo Auth ID and Auth Token). Credentials are automatically validated upon saving. Go to **Phone Numbers** to buy numbers directly through your connected carrier or verify existing company numbers for outbound Caller ID use. Open your agent in **Agent Studio**, switch to the **Call Tab**, and choose the **Telephony Provider** and verified **Caller ID**. Save your changes. *** ## Configuration Example ### Complete Call Tab Configuration Below is an example of a complete Call Tab configuration: ```yaml theme={null} # Agent Studio - Call Tab Settings max_call_duration: 300 # 5 minutes maximum call duration silence_timeout: 10 # 10 seconds silence timeout telephony_provider: "Plivo" # Route through Plivo caller_id: "+14155550199" # Verified company caller ID ``` ### Expected Call Behavior ```mermaid theme={null} sequenceDiagram autonumber participant Callee as Customer / Callee participant Carrier as Telephony Carrier (Plivo) participant Agent as Voice Agent Carrier->>Callee: Dial outbound call with Caller ID (+14155550199) Callee->>Carrier: Answers call Carrier->>Agent: Call connected (Max Duration timer: 300s starts) Agent->>Callee: "Hello! How can I assist you today?" Note over Callee,Agent: Conversation in progress Callee->>Agent: "I have confirmed the booking, thank you!" Agent->>Callee: "You're all set. Have a wonderful day!" Note over Callee,Agent: Silence detected (Silence Timeout: 10s timer starts) Callee-->>Agent: (No response for 10 seconds) Agent->>Carrier: Silence timeout reached -> Terminate call Carrier->>Callee: Call ended gracefully ``` * **Outbound Caller Display:** The callee sees `+14155550199` on their incoming call screen. * **Silence Handling:** If the conversation ends and the callee doesn't hang up, the agent waits `10 seconds` of silence before automatically hanging up. * **Duration Limit:** If the call exceeds `300 seconds` (5 minutes), the session is terminated automatically to prevent open-line billing.