User`s manual

Connection Option (Opt8x) and Cable Wiring
Smartio C168H/PCI User’s Manual 5-7
Type 3: To connect Smartio C168H/PCI to a DTE with 3-pin wiring.
If the Hardware flow control feature is set to ON, you must loop back (or short) RTS
with CTS, and DSR with DTR, DCD on the MOXA side, indicated with dash-lines in
the following diagrams. If the Hardware flow control feature is set to OFF, you can
just leave RTS, CTS, DSR, DTR, DCD open, ignoring the connections indicated with
dashed lines.
PC COM2 port, Serial Printer,
Terminal, or any DTE Device
Opt8A/S
Opt8A/S DTE Device
DB25 Female DB25 Male
RxD 2 2 TxD
TxD 3 3 RxD
GND 7 7 GND
RTS 5 4 RTS
CTS 4 5 CTS
DTR 20 6 DTR
DST 6 20 DSR
DCD 8 8 DCD
PC COM2 port, Serial Printer,
Terminal, or any DTE Device
Opt8B/C
Opt8B/C DTE Device
DB25 Male DB25 Male
TxD 2 2 TxD
RxD 3 3 RxD
GND 7 7 GND
RTS 4 4 RTS
CTS 5 5 CTS
DSR 6 6 DTR
DTR 20 20 DSR
DCD 8 8 DCD