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Pin
1
2
3
4
5
6
7
8
9
As the RS232 interface has the above electrical characteristics, it can only realize
point-to-point communication.
RS232 communication wiring diagram is shown in the figure below:
2. RS422
The full name of RS422 interface standard is "Electrical Characteristics of
Balanced Voltage Digital Interface Circuit", which defines the characteristics of the
interface circuit. RS422 adopts four-wire plus ground wire (T+, T-, R+, R-, GND),
full-duplex, differential transmission, multi-point communication data transmission
protocol. It USES a balanced transmission line that is unidirectional/non-reversible,
http:// www.odotautomation.com
9-pin RS232 serial port（DB9）
Name
CD
RXD
TXD
DTR
GND
DSR
RTS
CTS
RI
Function
Carrier detect
Receive data
Send data
Data terminal ready
Signal ground
Data ready
Request to send
Clear to send
Ring alert
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