Custom Sip Trunk - extension transfers on warm transfer

Support Help
1

I originally connected my phone number through sip trunking. When the agent takes the call and transfers via a dynamic warm transfer to an extension I have inputted, I hear the hold tone but I cant see any logs of a transfer actually made to my internal extension and the call logs just show no answer?

2

Based on the available sources, when using warm transfer with extensions through SIP trunking, there are a few configuration points to verify:

For the transfer target, you can set the transfer number to be a number in e.164 format, a SIP URI in the format of sip:username@domain, or a dynamic variable that gets substituted at runtime(1). When setting the transfer number extension, the extension must be 0-9, ‘*’, ‘#’ (e.g., 123#)(1).

If your transfer destination is not in e.164 format, you can choose to keep the input as is by choosing raw format when using custom telephony(1). This can be useful when you want to transfer to internal pseudo numbers(1).

For warm transfers specifically, several settings affect the transfer behavior(1)(2):

  • Enable human detection: When enabled, the agent will check if a human is present after the transfer target answers(1)(2). The original caller will only be connected once a human is detected(1)(2).

  • Agent detection timeout: The maximum amount of time the AI agent will wait to determine whether the transfer target is a human(1)(2). The caller is connected only if human detection succeeds within this timeframe(1)(2). Otherwise, the transfer is marked as failed(1)(2). The default timeout is 30 seconds(1)(2).

  • Navigate IVR: Provide a prompt to help you navigate if the transfer target is an IVR system(1)(2).

The “no answer” status in your call logs could indicate that the human detection timeout expired before detecting a human on the extension, or the extension itself didn’t answer within the configured timeout period.

I recommend checking your warm transfer configuration settings, particularly the agent detection timeout and whether human detection is enabled, as these directly impact whether the transfer completes successfully.

3

Hello @Zac_Pagan
Can you share a call id so I can check it?

4

I don’t have specific information about a user named @Zac_Pagan or their call ID in the available sources.

If you’re looking to retrieve call information in Retell AI, you can use the Get Call API endpoint with a specific call ID(1). The call ID format typically looks like "119c3f8e47135a29e65947eeb34cf12d"(1) or "Jabr9TXYYJHfvl6Syypi88rdAHYHmcq6"(2).

To retrieve call details, you would make a GET request to /v2/get-call/{call_id}(1).

If you need help with a specific call issue, please provide the call ID and I can help you understand what information you can retrieve about it.

5

Hi Omar,

Caller ID:

call_be1ca415617633429aba6f39