Barge-in is not a parameter which can be set by an application. It is solely determined by the prompt associated with the GetSpeech and GetDigits PerCL commands.

Barge-in is a useful Voice User Interface (VUI) construct for controlling what a Caller must hear and what they should be able to barge through when responding to a dialog prompt. For instance, if you need to play a legal disclaimer before the Caller can respond to a menu option you should not allow barge-in for the legal disclaimer prompt, but may allow barge-in for the menu prompt.

Be careful when ordering your Play/Say/GetSpeech/GetDigits commands. In the example described in the previous paragraph, you would put the legal disclaimer prompt in a Say or Play command before the GetDigits command. Then, you would put the menu prompt in a Play or Say command nested within the GetDigits command.