Communication Format; Header Block Format (Fixed Length) - NEC LCD4020-BK-AV - 40IN LCD 1200:1 1366X768 60HZ Dvi-d 8MS Manual

4. Communication Format

Header
The command packet consists of four parts, Header, Message, Check code and Delimiter.
Sequence of a typical procedure to control a monitor is as follows,
[A controller and a monitor, two-way communication composition figure]
Controller
Delimiter
Delimiter
Delimiter
Delimiter

4.1 Header block format (fixed length)

Reserved
SOH
'0'
st nd
1 2
st
1 byte) SOH: Start of Header
ASCII SOH (01h)
nd
2 byte) Reserved: Reserved for future extensions.
On this monitor, it must be ASCII '0'(30h).
rd
3 byte) Destination: Destination equipment ID. (Receiver)
Specify a commands receiver's address.
This value must match the "Monitor ID No." set in the OSD.
Message
Get Parameter
Check Code
Message
Get Parameter Reply
Header Message
Set Parameter
Check Code
Message
Set Parameter Reply
Header Message
Get Parameter
Check Code
Message
Get Parameter Reply
Header Message
Save Current Setting Command
Check Code
Message
Destination Source
rd th
3 4
Check Code Delimiter
Monitor
Header
Check Code
Delimiter
Header
Check Code
Delimiter
Header
Check Code
Delimiter
Header
Header
Message
Message Message
Type Length
th th
5 6
(2/40)
The controller sends command to
get a value from the monitor that
you want to change.
The monitor replies a current value
of the requested item.
The controller sends commands to
set an adjusted value.
The monitor replies
controller for confirmation.
The controller sends command to
get a value for confirmation.
The monitor replies an adjusted
value.
The controller requests to store
the adjusted value to the monitor.
Check code Delimiter
th
-7
to the