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Chapter 2
- Hardware Installation
SD170
17
Connecting External Serial Ports
Your COM port may come mounted on a card-edge bracket. Install the card-edge bracket to
an available slot at the rear of the system chassis then insert the serial port cable to the COM
connector. Make sure the colored stripe on the ribbon cable is aligned with pin 1 of the COM
connector.
The pin assignment of each mode mentioned above is listed below.
Pin RS232 RS232 with PWR
(COM 1 only)
RS422 Full Duplex
RS485
1
DCD-
+12V
TXD-
Data-
2
RD
RD
TXD+
Data+
3
TD
TD
RXD+
N.C.
4
DTR-
DTR-
RXD-
N.C.
5
GND
GND
GND
GND
6
DSR-
DSR-
N.C.
N.C.
7
RTS-
RTS-
N.C.
N.C.
8
CTS-
CTS-
N.C.
N.C.
9
RI-
5V
N.C.
N.C.
▼
COM Port Pin Assignment
COM (Serial) Ports
►
Rear I/O Ports
COM 1
►
COM Port Internal Connector
►
1
2
9
The serial ports are asynchronous communication ports with 16C550A-compatible UARTs that
can be used with modems, serial printers, remote display terminals, and other serial devices.
COM 1 (Rear Port) and COM 2 (Internal Port) support three serial modes, i.e. RS232, RS422,
and RS485. COM 3 and COM 4 (Internal Ports) support Standard RS232 as well as RS232 with
Power. Serial modes of COM 1 and COM 2 are configured via BIOS settings as instructed in the
next chapter. RS232 with/without power of COM 3 and COM 4 can be configured via jumper
settings as previously instructed in this chapter.
COM 4
COM 2
COM 3