Message Block Format - NEC V321-2 Communications Manual

ASCII 'B' (42h): Command reply.
ASCII 'C' (43h): Get current parameter from a monitor.
ASCII 'D' (44h): "Get parameter" reply.
ASCII 'E' (45h): Set parameter.
ASCII 'F' (46h): "Set parameter" reply.
th th
6 -7 bytes) Message Length:
Specify the length of the message (that follows the header) from STX to ETX.
This length includes STX and ETX.
The byte data must be encoded to ASCII characters.
Ex.) The byte data 3Ah must be encoded to ASCII characters '3' and 'A' (33h and 41h).
The byte data 0Bh must be encoded to ASCII characters '0' and 'B' (30h and 42h).

4.2 Message block format

"Message block format" is allied to the "Message Type" in the "Header".
Refer to the section 6 "Message format" for more detail.
1 ÿ Get current parameter
The controller sends this message when you want to get the status of the monitor.
For the status that you want to get, specify the "OP code page" and "OP code",
refer to "Appendix A. Operation code table".
"Message format" of the "Get current parameter" is as follows,
STX

Refer to section 5.1 "Get current parameter from a monitor." for more details.
2 ÿ Get Parameter reply
The monitor will reply with the status of the requested item specified by the controller
in the "Get parameter message".
"Message format" of the "Get parameter reply" is as follows,
Result
STX
Hi Lo

Refer to section 5.2 "Get parameter reply" for more details.
3 ÿ Set parameter
The controller sends this message to change a setting of the monitor.
Message format of the "Set parameter" is as follows,
OP code
STX page
Hi Lo

Refer to section 5.3 "Set parameter" for more details.
Header
OP code page OP code
Hi Lo Hi
OP code
OP code
page
Hi Lo Hi Lo
OP code Set Value
Hi Lo MSB
Message Check code
ETX
Lo
Type Max value
Hi Lo MSB
ETX
LSB
(4/37)
Delimiter
Current Value
LSB MSB LSB
ETX