function 'MESSAGE_DATA'
[Synopsis] Read or write custom data attached to a message. [Description] This function will read from or write a value to a text message. It is used both to read the data out of an incoming message, as well as modify a message that will be sent outbound. NOTE: If you want to set an outbound message to carry data in the current message, do Set(MESSAGE_DATA(<key>)=${MESSAGE_DATA(<key>)}). [Syntax] MESSAGE_DATA(argument) [Arguments] argument Field of the message to get or set.
[See Also] Asterisk app: MessageSend()