Hey guys, I hooked up telnyx numbers through the api key but it seems like the voice isn't connecting properly and the customer isn't able to hear the agent. https://cdn.discordapp.com/attachments/1435298378463576185/1435298379491184733/Screenshot_2025-11-04_at_11.01.18_AM.png?ex=690b7548&is=690a23c8&hm=9b0dd4339f519d55c965a260f0c30d93b9ab00524488fd9daa9093d771b0dfb0& https://cdn.discordapp.com/attachments/1435298378463576185/1435298380304748615/Screenshot_2025-11-04_at_11.03.05_AM.png?ex=690b7548&is=690a23c8&hm=ec4a02641a25ec47f908d0e7376ddf7069568588f4be6dc455b03e5c9d99f275&

To resolve your Telnyx voice connection issues, switch to SIP integration for more reliable audio. Here’s how to create a SIP trunk credential in Vapi:

bash
curl -X POST https://api.vapi.ai/credential \
  -H "Content-Type: application/json" \
  -H "Authorization: Bearer YOUR_VAPI_PRIVATE_KEY" \
  -d '{
    "provider": "byo-sip-trunk",
    "name": "Telnyx Trunk",
    "gateways": [{ "ip": "sip.telnyx.com", "inboundEnabled": false }],
    "outboundAuthenticationPlan": {
      "authUsername": "YOUR_SIP_USERNAME",
      "authPassword": "YOUR_SIP_PASSWORD",
      "sipRegisterPlan": { "realm": "sip.telnyx.com" }
    }
  }'

Replace the placeholders with your actual credentials and test your calls again. This should improve voice connectivity between Vapi and Telnyx. Source: - [Telnyx SIP integration documentation](https://docs.vapi.ai/advanced/sip/telnyx)

so I switched to telnyx SIP trunk

Hi swiftdev, To integrate your Telnyx SIP trunk with Vapi for efficient call handling, follow these summarized steps: 1. Configure Outbound Calling: - In the [Telnyx Portal](https://portal.telnyx.com/#/outbound-profiles), set up or select an outbound voice profile. - Add Vapi as a connection under the "Connections and Applications" tab. 2. Integrate SIP Trunk: - Log in to Vapi and navigate to Organization Settings. - In the API Keys section, copy your Private Key. - Go to Voice / SIP Trunking / Create, and add

sip.vapi.ai

as the FQDN. - Assign your Telnyx number to the SIP trunk in the Numbers tab. - Ensure inbound settings are configured to match your Vapi SIP URI. 3. Setup Authentication: - Use the Vapi API to create a new SIP trunk credential, providing the necessary authentication credentials (username/password or IP-based), and link it to your phone number. 4. Outbound Call Setup: - Create an outbound profile in Vapi, assigning your configured Telnyx SIP trunk. - Use the Vapi API to initiate outbound calls. For detailed steps, refer to the [Telnyx SIP Integration Guide](https://docs.vapi.ai/advanced/sip/telnyx) and [SIP Trunking Guide](https://docs.vapi.ai/advanced/sip/sip-trunk). This setup will ensure your AI voice assistants can handle calls effectively.