When specifying a destination phone number in the Barritel API, if appropriate you may also append an extension to it. When the call is answered, the DTMF tones for the extension digits will be sent before the caller is connected.

This can be useful, for example, if the destination number has an IVR menu inviting the caller to enter an option or their required extension and you want the system to automatically navigate through that menu in order to direct the call to a specific extension or department and connect to a human.

To define an extension, put the extension digits after a comma or a p at the end of the phone number.

Additional commas and/or "p"s can be put amongst digits of the extension in order to create additional pauses between the DTMF tones sent. A comma represents a pause of 2 seconds, a "p" represents a pause of 0.5 seconds. Longer pauses can be defined by simply including more commas or "p"s, or both.