Enable Verified Caller ID (Indian Airtel Number) for Outbound Calls

Support Help
1

Hi Retell AI Team,

I have already:
• Created an agent
• Added billing
• Purchased an international phone number

I want to use my own Indian Airtel mobile number (+91)
as Caller ID for OUTGOING calls only.

Use case:
• Official, non-promotional healthcare coordination calls
• No incoming calls required
• No SIP trunking needed
• OTP-based number verification is acceptable

Currently, I do not see any option for:
• BYON
• Verified Caller ID
• Add my own number

Could you please confirm:

  1. Is Indian mobile number Caller ID supported on my account? (Yes/No)
  2. If yes, please enable BYON / Verified Caller ID for my account
  3. If not supported, please confirm clearly so I can plan alternatives

Thank you,
Aditya Kumar
India

2

Using your own mobile number as caller ID for outbound calls requires integrating with Retell AI through custom telephony via SIP trunking(1). The platform supports importing phone numbers from custom telephony providers using the Import Phone Number API(2).

To use your Indian Airtel mobile number as caller ID, you would need to work with a telephony provider that supports elastic SIP trunking(1). The process involves setting up a SIP trunk with your provider and configuring it to use your personal number as the outbound caller ID(1).

For verified caller ID specifically, one documented approach involves verifying your personal number with a telephony provider like Telnyx, then setting it as a caller ID override in your SIP connection’s outbound settings(3). Calls routed through Retell’s SIP trunk using this configuration will display your personal number(3).

The Import Phone Number API requires these parameters(2):

  • phone_number in E.164 format (e.g., “+914157774444” for an Indian number)(2)
  • termination_uri for your SIP trunk(2)
  • Optional sip_trunk_auth_username and sip_trunk_auth_password(2)

Retell’s SIP server URI is sip:sip.retellai.com with IP block 18.98.16.120/30 for all regions(1). Transport methods supported include TCP (recommended), UDP, and TLS(1).

I cannot confirm from the available documentation whether Indian mobile numbers are specifically supported or if BYON/Verified Caller ID features are enabled by default on your account. For account-specific feature enablement and India-specific telephony support, please contact:

3

Hello @infosuzi6

If your phone number supports sip tunrking, then you can connect it

Or you can use the dial to SIP method

4

You’re correct—there are two primary methods to integrate custom telephony providers with Retell AI(1).

Method 1: Elastic SIP Trunking (Recommended)(1)

This is the recommended approach for integrating with telephony providers that support elastic SIP trunking(1). You’ll need to set up a SIP trunk and configure your number to point to it, then import that number to Retell(1). When using this method, all telephony functionalities supported by Retell numbers will also be supported here, assuming your telephony provider supports them(1).

Retell’s SIP server URI is: sip:sip.retellai.com(1)

IP block for traffic: 18.98.16.120/30 (All regions), 143.223.88.0/21 (certain United States traffic), 161.115.160.0/19 (certain United States traffic)(1)

Transport methods supported include TCP (Recommended), UDP, and TLS(1).

Method 2: Dial to SIP URI(1)

If your telephony provider doesn’t support elastic SIP trunking, or you have a more complicated telephony setup, you can use this method(1). With this approach, Retell doesn’t directly make or receive calls—instead, your system dials the call to the respective SIP URI(1). This requires you to have code to handle integration with your telephony provider(1).

To obtain the SIP URI for a call, you would call the Register Phone Call API(1). You’ll get a call_id back from this API, which you use to construct the SIP URI(1):

SIP URI: sip:{call_id}@sip.retellai.com(1)

When using this method, you won’t be able to utilize Retell’s transfer call feature, as Retell doesn’t have access and control over the telephony provider and number(1). However, you can implement your own transfer logic using a custom function(1).

**