A Link is triggered when two voice channels are linked together and voice data exchange commences.
Several Link events may be seen for a single call. This can occur when Asterisk fails to setup a native bridge for the call.This is when Asterisk must sit between two telephones and perform CODEC conversion on their behalf.

public delegate void LinkEventHandler(
	Object sender,
	LinkEvent e
)

Public Delegate Sub LinkEventHandler ( 
	sender As Object,
	e As LinkEvent
)

public delegate void LinkEventHandler(
	Object^ sender, 
	LinkEvent^ e
)

type LinkEventHandler = 
    delegate of 
        sender : Object * 
        e : LinkEvent -> unit