ImportVar( ) Sets a variable based on a channel variable from a different channel
ImportVar(newvar=channel,variable)
Sets variable newvar to variable as evaluated on the specified channel (instead of the current channel). If newvar is prefixed with _, single inheritance is assumed. If prefixed with _ _, infinite inheritance is assumed.
; read the Caller ID information from channel Zap/1
exten => 123,1,Answer( )
exten => 123,1,ImportVar(cidinfo=Zap/1,CALLERID)