GTD Manipulation

Cisco VVB enables a VoiceXML script to access GTD parameters before and after a call transfer, to append and override GTD parameters, and to create new GTD messages. For example, if an incoming call setup event contains a GTD IAM message, the <transfer> element uses the IAM message and overrides or appends the parameters specified by the <transfer> GTD attributes. If the incoming setup event does not contain the IAM message, and if the VoiceXML script wants to send a GTD message on the outgoing leg, it creates a new IAM GTD message and adds or appends the required GTD parameters to it. The VoiceXML script sends this new GTD message to the outgoing leg using the <transfer> element. The GTD messages can only contain parameters specified in the tables in this document.

GTD messages and their individual parameters are represented as JavaScript objects. The GTD message object is at the top level, and the individual parameters are represented at the subobject level. The individual subfields of supported GTD parameters can be accessed and modified as properties of the parameter subobject. GTD messages received on an incoming call leg during the setup event are represented by the Cisco VoiceXML session variable com.cisco.signal.gtdlist which is an array of GTD objects indexed by the call signal event name (setup_indication). This session variable allows the VoiceXML script to only read the GTD parameters received in the setup message. Being a session variable, the VoiceXML script has read-only access to the GTD parameters.

The Cisco VoiceXML shadow variable of the form <transfer_name>$.com.cisco.signal.gtdlist is used to read GTD parameters on the outgoing leg after the call transfer terminates. This shadow variable is a read-only variable representing an array of GTD objects indexed by the call signal event name. Reading a valid parameter that is not included in a GTD message results in the return value undefined. Setting a parameter that is not supported causes an exception error event to be thrown by the system.

The object com.cisco.objclass.gtd is a Cisco object class that is used to modify an existing GTD message or create a new GTD message that allows the VoiceXML script to have read-write access to the GTD messages.

The VoiceXML script can use the Cisco attribute cisco-gtd with the <transfer> element to send a modified GTD message to the outbound call leg. The attribute represents the GTD object that is sent on the outbound leg. cisco-gtd is also used with the <disconnect> element to send a GTD message during a call release.