Hitachi KP-FM500WCL Operation Manual page 19

(1) Transmission from master (normal process)
HITACHI
Slave
(KP-FM500WCL
KP-FMD500WCL)
① Session starts when ENQ is sent from master to slave.
② Slave acknowledges by returning ACK to master.
③ Master sends data to slave.
④ Slave acknowledges receipt of data by again returning ACK to master and end the handshake.
(2） Master reads data (normal process)
HITACHI
Slave
(KP-FM500WCL
KP-FMD500WCL)
① Session starts when ENQ is sent from master to slave.
② Slave acknowledges by returning ACK to master.
③ Master sends read command to slave.
④ Slave receives read command, then acknowledges by returning ACK code to master.
⑤ Slave sends read data to master.
⑥ Master receives read data, then acknowledges by returning ACK code to slave.
ENQ code (05h）
ACK code (06h)
2
Transmit data (ASCII code)
ACK code (06h)
4
ENQ code (05h)
ACK code (06h)
2
Read command (ASCII code)
ACK code (06h)
4
Read data (ASCII code)
5
ACK code (06h)
1
3
Master (Machine)
1
3
Master (Machine)
6
10