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How to add Prefix in CallerID in BYOC Outgoing Calls

Scenario and use case

The customer's service provider has a requirement that Twilio send a prefix in the Caller ID in BYOC outgoing calls made from Twilio.


Customers can pass a prefix in the Caller ID when making a BYOC outgoing call via <Dial> Twiml. For example 

<Dial callerId="12345+14151234567><Number byoc="{Your BYOC=Trunk_SID}">+14158675309</Number></Dial>

Here, the 12345 value in the caller ID is a way of adding a prefix along with the actual Caller ID value of +14151234567.


We can pass prefixes in Caller ID only in <Dial> Twiml calls.  We can not pass the same prefix in caller ID in outgoing API or conference participant API calls.

In order to pass a prefix in caller ID in <Dial> Twiml, a customer's account needs to have the "Allow Any Caller ID" flag enabled.


In order to enable "Allow Any Caller ID" on your account, please contact Twilio support. The team would request certain details from the customer and would send these details to our internal team for approval.  If all is good from the internal team, this flag will be enabled by them and the customer would be notified by support and the customer can then start sending the prefix in caller ID in BYOC outgoing calls.

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