Command Block Format; Communication Protocol - Sony Trinitron PVM-14M2MDU Interface Manual

Command Block Format

Data communication between the remote control
device and the monitor is performed in accordance
with the following format.
STX Byte Count
1 byte 1 byte
• STX: start of text code value equals 02hex.
• Byte Count
This indicates the number of data bytes (maximum
255 bytes) which have been inserted between this
byte and the Checksum byte.
Values 00hex, 01hex, 02hex are illegal values.
• Destination address:
One byte address value which defines who the
message is for. Value 01hex should be specified.
• Source address:
One byte address value which defines where the
message came from. This is who to reply to with
the message. Value from 41hex to 7Fhex should be
specified.

Communication Protocol

The remote control device should take the initiative in
communication between the remote controller and the
monitors.
The monitor will carry out one of the following three
actions within 9 milliseconds of receiving the
message.
• When the received message is an undefined message
or a communication error occurs then issue: NAK
(05hex)
• When the received command is a question then
issue: Specific Reply + Data
• When the received command is anything else issue:
ACK
Destination
Source Address
Address
1 byte 1 byte
• Command Block
• Checksum
The remote control should not issue any other
commands until the response has been received from
the monitor.
The remote control should not leave a gap between
bytes to be transmitted of more than ten milliseconds.
Otherwise the monitor will treat the message as
received in ERROR.
If the remote control unit receives a NAK from the
monitor it must wait more than ten milliseconds
before transmitting any more messages.
Command Block
n bytes
This designates a particular command. Refer to
"Command Description" for the details.
This value is set so that the bottom eight bits of the
sum of all bytes from the byte count to the
checksum inclusive are zero.
Communication
Checksum
1 byte
3