8
Chapter 2
Documentation Number 3PCIOSD2x-3903 Manual
B&B Electronics Mfg Co – 707 Dayton Rd - PO Box 1040 - Ottawa IL 61350 - Ph 815-433-5100 - Fax 815-433-5104
B&B Electronics Ltd – Westlink Comm. Pk. – Oranmore, Galway, Ireland – Ph +353 91-792444 – Fax +353 91-792445
Table 1: RS-232 Pinouts
RS-422 Mode
To configure one port for RS-422 mode, 7 jumpers must be
set/checked. The following settings configure Port 1 as RS-422.
Jumpers for Port 2 shown in italics
1.
Set the four jumpers of JP3 (A-D) to the "422/485" (right)
position.
Use JP5 (A-D) for Port 2.
2.
Set the top jumper "TX" of JP4 to the “422” (left) position.
Use
"TX" of JP6 for Port 2.
3.
Set the second jumper "RX" of JP4 (Port1) to the “422” (left)
position.
Use "RX" of JP6 for Port 2.
2.
The bottom jumper "Termination" of JP4 switches the 120
Termination resistor IN or OUT.
Use JP6 for Port 2.
Typically
this resistor is not used. In some cases using high baud rates
and very long cables, termination is needed.
See B&B’s free
RS-422/485 Application Note
, Termination section, page 16,
for more information (available on our websites).
4.
The top Control jumper "Port 1" of JP2 is unused in RS-422
mode.
The lower Control jumper "Port 2" is unused in RS-422
mode for Port 2.
Figure 3 shows the jumper configuration for both ports set to RS-422
mode, with termination out and *1 clock enabled.
Name
Description
Direction
DB9M Pin
DCD
Data Carrier Detect
Input
1
RD
Receive Data
Input
2
TD
Transmit Data
Output
3
DTR
Data Terminal Ready
Output
4
GND
Signal Ground
------
5
DSR
Data Set Ready
Input
6
RTS
Request to Send
Output
7
CTS
Clear to Send
Input
8
NC
Not Connected
------
9
