My current system contains two different SIP Trunks, Call Comes in -> Vapi -> Ytel queue. Routing is all working correctly, problem is phone numbers within my Ytel queue are showing up as the DID from Vapi. Call logs within vapi show correct caller id. Any ideas on how to preserve the call id when transferring?

Thanks for sharing the details. To help pinpoint the issue, could you confirm whether your SIP trunk and transfer configuration in Vapi are set to pass the original caller ID (not the Vapi DID) to Ytel, and if SIP REFER is enabled on both sides? This will help determine if the caller ID is being overwritten during the transfer process. If you can share the transfer method (e.g., blind or warm transfer) and whether you are using any custom SIP headers, that would also be helpful. Sources: - [Vapi SIP Trunk Documentation](https://docs.vapi.ai/advanced/sip/sip-trunk) - [Vapi Call Forwarding & Transfer Troubleshooting](https://docs.vapi.ai/phone-calling/in-call-control/transfer-calls/debug-forwarding-drops)

SIP Refer does not seem to be supported by Ytel.

Hi, To ensure the original caller’s number is preserved during a SIP transfer, you can include the

callerId

field using the

{{customer.number}}

variable in your destination configuration:

{
  "tools": [
    {
      "type": "transferCall",
      "destinations": [
        {
          "type": "sip",
          "sipUri": "sip:yourqueue@ytel.example.com",
          "callerId": "{{customer.number}}"
        }
      ]
    }
  ]
}

The

{{customer.number}}

variable is automatically resolved by Vapi to the original inbound caller’s phone number. This value is then passed as the FROM header in the SIP INVITE sent to your SIP provider (e.g., Ytel), ensuring proper caller identification is maintained during the transfer.