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RS-232↔RS-422/485 CONVERTER (DATA ONLY)
3. Configuration
Here’s how to configure the RS-232↔RS-422/485 Converter (Data Only) for your
application (refer to Figure 3-1 on the next page for the location of components
on the circuit board):
CAUTION!
The Converter’s circuit board can be damaged by static electricity, so take
every reasonable precaution against it. Always discharge yourself
on a
metal surface before opening the Converter or touching the board; if
possible, stand
on an anti-static mat and wear a grounding strap or anti-
static gloves.
1. If your Converter is a standalone IC107A-R3 or IC107AE-R3 model: Open the
Converter by unscrewing the single screw on the bottom of its case and taking
the top of the case off.
2. Set the Converter’s RS-232 port to DTE or DCE as necessary for your
application. For the RS-232 port to function as a DTE device, put the DIP-
switch block in jumper socket XW1B. For the RS-232 port to function as a
DCE device, leave the DIP-switch block in jumper socket XW1A (the factory-
default setting). Whichever socket the block is in, make sure that all of its
individual DIP-switch positions are always set to ON.
3. Set jumper W15 to select how the Converter’s RS-422/485 driver is enabled. If
you want the driver to be permanently enabled, place the jumper across
W15’s pins B and C. If you want to use the RS-232 DTR or RTS signal to
enable the RS-422/485 driver, leave W15 in its factory-default position with
the jumper across pins A and B. (To have DTR enable the driver, leave
jumper W18 in its factory-default position with the jumper across pins A and B.
To have RTS enable the driver, place the W18 jumper across pins B and C.)
4. Some applications require the RS-422/485 interface to be terminated.
A resistor network can provide this termination on the Converter at the
RS-422/485 input receiver pins (RXA and RXB). Use DIP switch S2 to enable
or disable termination: If you move S2 to the “TERM” position, the resistor
network is connected across the line, and the RS-422/485 interface is
terminated. If you leave S2 in its factory-default “UNTERM” position, no
connection to the resistor network is made, and the interface is not
terminated.