5.5.3 NULL Message
The NULL message returned from the monitor is used in the following cases;
To tell the controller that the monitor does not have any answer to give to the host (not
ready or not expected)
Following operations need a certain time for to execute, so the monitor will return this
message when another message is received during execution.
Power ON, Power OFF, Auto Setup, Input, PIP Input, Auto Setup and Factory reset.
Complete "NULL Message" command packet as follows;