df570f0a_all_Control__CCXML_Version_1_0__Description
[Name] callerid [Required] false [Type] ECMAScript Expression [Default Value] none [Description] 
An ECMAScript expression which returns a string defining the caller identity to be used when making the outbound connection. The format of this information is protocol and platform specific but might consist of a telephone URI, as described in [RFC3966] or a SIP URI as described in [RFC3261]. Note: An implementation platform is not required to use the specified data and certain protocols and network elements may prevent its use. If the platform does not support the specification of callerid it must raise a connection.progressing event and indicate that the use of callerid is not supported.
Voice Browser Call Control: CCXML Version 1.0