@Fourshoe To pass the original call recipient's phone number into the call transfer, you can use one of the following methods: 1. **Query Parameter**: If the transfer destination supports URL parameters, you can append the original recipient's phone number as a query parameter in the transfer URL. 2. **SIP Header**: You can include a custom SIP header with the original call recipient's phone number when initiating the transfer. The header could be named

X-Original-Recipient

or something similar, depending on the conventions of the SIP infrastructure you're using. 3. **DTMF**: Although less common for passing phone numbers, you could theoretically use DTMF tones to send the phone number during the call setup. However, this would require the receiving system to be able to interpret DTMF tones as a phone number, which is not standard practice. Would you like to proceed with one of these methods, and if so, which one? If you need assistance with the implementation, please provide more details about the transfer destination and how you are currently handling calls.

Number 1 is ideal, transferring to a twilio number but the "From" number is always just the VAPI number I am calling from

@Fourshoe Great choice! To transfer the call and pass the original caller's phone number as a query parameter to a Twilio number, you'll need to modify the transfer URL to include this information. Here's how you can do it: 1. Retrieve the original caller's phone number from the call context. 2. Append this phone number as a query parameter to the transfer URL. For example, if your transfer URL is

https://example.com/transfer

, you would add

?originalCaller=+1234567890

to the end, where

+1234567890

is the original caller's number. 3. Initiate the transfer with the modified URL. The Twilio number that receives the transfer will then be able to access the original caller's phone number from the query parameters of the incoming request. If you're using VAPI to handle the call transfer, you would typically have an API or some backend logic to manage this. If you need to set this up or have any issues with the process, please let me know, and I can assist you further.

Using VAPI's in built call transfer function to transfer so I don't have granular control over the transfer url. Do you know how I can modify that url if using VAPI's transfer call function?

@Fourshoe If you're using VAPI's built-in call transfer function and you don't have direct control over the transfer URL, you'll need to work within the constraints of the VAPI system. Typically, VAPI would allow you to specify certain parameters when you're setting up the transfer. For example, if you're using a JSON object to define the transfer action, you might be able to include additional data that can be passed along with the transfer. However, if VAPI does not support appending custom data to the transfer URL directly, you may need to consider alternative methods. One potential workaround is to use a webhook or a callback URL that you control. When the transfer is initiated, VAPI can hit your webhook with the call details, and then you can redirect the call to the Twilio number with the original caller's phone number appended as a query parameter. Here's a high-level overview of how this might work: 1. Set up a webhook endpoint on your server that can handle incoming requests from VAPI. 2. When setting up the call transfer in VAPI, specify your webhook URL as the destination. 3. When VAPI hits your webhook, extract the original caller's phone number from the incoming data. 4. Construct the transfer URL with the original caller's phone number as a query parameter. 5. Respond to VAPI's request with instructions to redirect the call to the Twilio number using the constructed URL. If you need more specific guidance on how to implement this with VAPI, or if there are particular parameters or settings you're unsure about, please let me know, and I'll do my best to assist you.

Wait what is a transient phone number?

@Fourshoe A transient phone number is a temporary phone number that is typically used for a single call or a short duration of time. It's often used in scenarios where maintaining privacy is important, such as in two-factor authentication processes, customer service interactions, or any situation where you don't want to expose personal phone numbers. In the context of VAPI (Voice API), a transient phone number can be used to mask the actual phone number of either the caller or the recipient. When the call is made using a transient number, the recipient sees this temporary number instead of the real caller's number. Similarly, the caller can also see a transient number instead of the real recipient's number. Transient numbers are useful for protecting user privacy and are also used to prevent abuse by ensuring that phone numbers cannot be harvested for spam or unsolicited calls. They are typically provisioned dynamically for each call and are released back into the pool of available numbers after the call ends or after a certain period of time. If you have any further questions or need assistance with implementing transient phone numbers in your VAPI application, feel free to ask!

Whats the process to transfer a call if I am using a custom llm?

@slickVik Please ask support for more info on this.