Minolta Di551 Service Manual page 129

OTHER KINDS OF CONTROL
2. Signals
a. Input signals
(1) S_IN2 (OB1 to ICB)
Serial data which informs ICB (image control
board) of the operation state of OB1 (operation
board/1).
(2) /CTS2 (OB1 to ICB)
Signal which indicates that data can be sent from
OB1 (operation board/1) to ICB (image control
board)
When this signal is at the high level ([H]), ICB
stops sending the S_OUT2 signal.
(3) /DSR2 (OB1 to ICB)
Acknowledgment signal which is returned each
time OB1 (operation board/1) receives one-byte
data from ICB (image control board)
b. Output signals
(1) S_OUT2 (ICB to OB1)
Serial data which informs OB1 (operation board
/1) of the machine status that is known to ICB
(image control board).
(2) /RTS2 (ICB to OB1)
Signal which indicates that data can be sent from
ICB (image control board) to OB1 (operation
board/1).
When this signal is at the high level ([H]), OB1
stops sending the S_IN2 signal.
(3) /DTR2 (ICB to OB1)
Acknowledgment signal which is returned each
time ICB (image control board) receives one-
byte data from OB1 (operation board/1).
2-P-8