DA-681C Series HW UM
Hardware Installation
2-8
3.
Insert the USB device into the USB port inside
the DA-681C computer.
4.
Place the USB plate on the rail and push it down
as close to the USB device as possible. Finally,
fasten the screw on the plate to secure the USB
device.
5.
Put back the top cover of the computer.
Connecting to a Keyboard and Mouse
Connectors for a keyboard and a mouse are located on the rear panel of the computer. Both connectors are
PS/2 interfaces; you can directly connect a keyboard and a mouse using these connectors.
Serial Ports
The DA-681C comes with 2 software-selectable RS-232/422/485 serial ports (P1 and P2) with DB9
connectors, which are located on the rear panel.
Pin
RS-232
RS-422
RS-485 (4-
wire)
RS-485 (2-
wire)
1
DCD
TxDA(-)
TxDA(-)
–
2
RxD
TxDB(+)
TxDB(+)
–
3
TxD
RxDB(+)
RxDB(+)
DataB(+)
4
DTR
RxDA(-)
RxDA(-)
DataA(-)
5
GND
GND
GND
GND
6
DSR
–
–
–
7
RTS
–
–
–
8
CTS
–
–
–
In addition, there are 10 serial ports (P3 to P12) that use terminal blocks. Refer to the following table
for the pin assignments.
Pin
RS-232
RS-422
RS-485 (4-
wire)
RS-485 (2-
wire)
1
TxD
TxD(+)
TxDA(+)
–
2
RxD
TxD(-)
TxDB(-)
–
3
RTS
RxD(+)
RxDB(+)
Data(+)
4
CTS
RxD(-)
RxDA(-)
Data(-)
5
GND
GND
GND
GND
