(22/139)5.5.3 NULL MessageThe NULL message returned from the monitor is used in the following cases;Ø To tell the controller that the monitor does not have any answer to give to the host (notready or not expected)Ø A null message will be returned by the monitor if the “Start Proof of Play” command is sentand the monitor has already started Proof of Play.Ø A null message will be returned by the monitor if the “Stop Proof of Play” command is sentand the monitor has not started Proof of Play.Ø Complete "NULL Message" command packet as follows;01h-30h-30h-41h-42h-30h-34h-02h-42h-45h-03h-CHK-0DhSOH-'0'-'0'-'A'-'B'-'0'-'4'-STX-'B'-'E'-ETX-CHK- CRSTX Command code ETX'B' 'E'
