Quatech Asynchronous Communications Adapter DSC-200/300 - Manual (Page 9)

2 Hardware Configuration
The DSC-200/300 is automatically configured at boot time by the computer's
BIOS or operating system. There are no required switches or jumpers to set for
installation.
This chapter lists a number of jumper settings that control various hardware
features. Jumpers J1-J4, located in a column near the D-9 connectors, control the RS-422
or RS-485 signal line termination. Jumpers J5-J8, located in a column just to the right of
J1-J4, control how signals are routed from the UARTs to the connector, as well as full- or
half- duplex operation. Jumpers J10-J13, grouped together at the end of the board
opposite the D-9 connectors, control special options.
Any changes from the factory default should be made before installing the
DSC-200/300 in the computer.
2.1 RS-422 or RS-485 Signal Line Termination
Jumpers J1-J4 allow the selection of 100-ohm RS-422 termination, 120-ohm RS-485
termination, or no termination at all. The factory default, shown in Figure 1, is RS-422
termination. For full details, see page 24.
1
2
3
RS-422 termination
(100 ohms)
(factory default)
Jumpers J1-J4
Figure 1 --- Factory default signal termination settings
Quatech DSC-200/300 User's Manual 9