Advantech PCI-1602UP, User Manual

Page: 61 / 68

51
PCI/ PCI Express-Communication
User Manual
Chapter 5
P
in Assignments
and
Wiring
For DTE to DCE connections, use a straight through cable (i.e., you don't have to reverse
lines 2 and 3, lines 4 and 5, and lines 6 and 20 since, in general, the DCE RS-232 interfaces
are reversed themselves).
Therefore, if you are not using CTS, RTS, DSR,DTR and DCD signals, short pins 4 and 5
together, and please short pins 6, 8,and 20 together.
5.2.2 RS-422 Signal Wiring
The RS-422 interface wiring is based on one-to-one principles. The transmit lines on
one side connect to the receive lines on the other side, and vice versa. With RS-422,
you can transmit and receive data simultaneously (full duplex). The connections are
as follows:
Terminator Resistors Setup
The signals DSR, DTR and DCD are shorted internally on the PCI-1601/1602/1611/
1612/1622 cards when operating in RS-422 mode.
A user can solder in termination resistors if necessary for impedance matching. The
card has two mounting spaces for termination resistors, but no resistors are installed
at the factory. Each pair of signal lines has a separate resistor (RxD+/-, TxD+/-).
Table 5.20: Terminal without Handshake
DB-25 Male Terminal, PC (DTE)
Pin Signal Pin Signal
2 TxD 3 RxD
3 RxD 2 TxD
4 RTS
5 CTS
7 GND 7 GND
6 DSR
20 DTR
8 DCD
Table 5.21: RS-422 DB9 Pin Assignment
DTE (Male DB-9) Terminal DTE
Pin Signal Pin Signal
1 TxD- 1 RxD-
2 TxD+ 2 RxD+
3 RxD+ 3 TxD+
4 RxD- 4 TxD-
5 GND 5 GND
6 RTS- 6 CTS-
7 RTS+ 7 CTS+
8 CTS+ 8 CTS+