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©Vecow SPC-4000 User Manual
GETTING TO KNOW YOUR SPC-4000
2.3.2 SPC-4020/SPC-4020A Rear I/O & Functions
2.3.2.1 Serial Port COM
V+ V
DC-IN 12V
Switch
On | Off
Isolated
COM 1
Isolated
COM 2
COM 3
COM 4
Serial port 1 to 4 (COM 1 to 4) can be configured for RS-232, RS-422, or RS-
485 with auto flow control communication. The default definition of COM 1 to
COM 4 is RS-232. If you want to change to RS-422 or RS-485, you can find the
setting in BIOS.
BIOS Setting
Function
COM 1 (Isolated)
COM 2 (Isolated)
COM 3
COM 4
RS-232
RS-422 (5-wire)
RS-422 (9-wire)
RS-485
RS-485 w/z auto-flow control
The pin assignments are listed in the following table :
Serial
Port
Pin
No.
RS-232
RS-422
(5-wire)
RS-422
(9-wire)
RS-485
(3-wire)
1 to 4
1
DCD
TXD-
TXD-
DATA-
2
RXD
TXD+
TXD+
DATA+
3
TXD
RXD+
RXD+
-----------
4
DTR
RXD-
RXD-
-----------
5
GND
GND
GND
GND
6
DSR
-----------
RTS-
-----------
7
RTS
-----------
RTS+
-----------
8
CTS
-----------
CTS+
-----------
9
RI
-----------
CTS-
-----------
