Hitachi CPX4 Manuel D'utilisation page 210

Decreasing the projector setting value (Decrement command)
(1) The PC sends the following decrement code to the projector.
Header + Command data ('05H' + '00H' + type (2 bytes) + '00H' + '00H')
(2) The projector decreases the setting value on the above setting code.
(3) The projector returns the response code '06H' to the PC.
When the projector cannot understand the received command
When the projector cannot understand the received command, the error code '15H'
is sent back to the PC.
Sometimes the projector cannot properly receive the command. In such a case,
the command is not executed and the error code '15H' is sent back to the PC. If
this error code is returned, send the same command again.
When the projector cannot execute the received command.
When the projector cannot execute the received command, the error code '1CH' +
'xxxxH' is sent back to the PC.
When the data length is greater than indicated by the data length code, the
projector ignore the excess data code. Conversely when the data length is shorter
than indicated by the data length code, an error code will be returned to the PC.
When authentication error occurred.
When authentication errorr occurred, the error code the '1FH' + '0400H' is sent
back to the PC.
NOTE
command or data.
[TCP #9715]
1. Protocol
Consist of header (1 byte) + data length (1 byte) + command data (13 bytes) +
2. Header
3. Data Length
4. Command data
5. Check Sum
This is the value to make zero on the addition of the lower 8 bits from the header
to the checksum.
6. Connection ID
Random value from 0 to 255 (This value is attached to the reply data).
Command Control via the Network (continued)
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