It won’t work as you expected.

The feature you mentioned is named “CallerId”. When you make a outbound call with RingCentral. You can specify a CallerID number and this number will be seen by the callee. 

BUT, you can only specify RingCentral numbers that you have ownership as CallerID. For example, you have an RingCentral extension and you bought 10 digital lines, each one with a different phone numbers. Then you can specify either of the 10 numbers as CallerId.  If a number is not yours, or the number is not even a RingCentral number, you cannot use the number as CallerID.

By the way, softphone SDK doesn’t support the callerId feature yet.  As I said above, even it supports this feature, it won’t work as you expected.
 

Quick question: How does RingCentral checks if I’m really the owner of a phone number ? I just pass calling phone number’s SIP credentials (username, password and authorization id), would RingCentral identify it with just them ?

Also is there any possibility to request a feature for making this possible ?

RingCentral has server side and database. It knows everything about a phone client. Like who are you, what’s your pricing plan, how many phone numbers you can use...etc.

I don’t think this feature will be supported because it would be a security issue. You are not supposed to make calls on behalf of a number which you have no ownership. Just like you cannot send email from an address which you don’t own (technically you could, but it will be classified as phishing/fraud).

Hi Tyler,

Many thanks, buddy.
You’ve been incredibly helpful, and I deeply appreciate your support.

Twilio offers a feature called “Verified Caller ID.”Here’s how the Twilio feature works: you add the number you want to use to Twilio's Verified Caller ID. Twilio then sends a verification code to that number via SMS. You enter the code back into Twilio, and the number becomes available for use.

While we’d like to stick with RingCentral, we continue to refer our new customers to you because of the outstanding support your team provides.

Is there any way we can discuss this feature request with the RingCentral team?
(By the way, we’ve already signed a partnership agreement with RingCentral through Telarus.)

— Beka, CTO

For such a new feature request, the best approach is to post it in the Ideals Portal, where other users/customers can vote and a dedicated RC team will evaluate the new ideal and take actions accordingly.

I have asked one of the senior project managers to check this thread. But there is no guarantee that the feature request will be addressed soon.

There is this article: https://support.ringcentral.com/article-v2/2297.html?brand=RC_US&product=RingEX&language=en_US

To be honest, I have no experience with it. Since it is not about programming or API, you will need to contact general support if you have questions about it:  https://support.ringcentral.com/

After you can make it work with the official RingCentral APP, we can check further if we can make it work with the softphone SDK. Please evaluate it and get back to us （or create a support ticket）.