RS
‐
232/485
RF
Modem
Product
Manual
–
MAN0782
‐
02
Page
13
RS-485 (4-wire) & RS-422 Operation
DIP Switch Settings & Pin Signals
Figure
2.10.
Figure
2.11.
RS
‐
485
(4
‐
wire)
and
RS
‐
422
Pins
used
on
the
female
RS
‐
232
(DB
‐
9)
DIP
Switch
Settings
Serial
Connector
Figure
2.12.
RS
‐
485
(4
‐
wire)
&
RS
‐
422
with
Termination
(optional)
Termination
is
the
120
Ω
resistor
between
T+
and
T
‐
.
DIP
Switch
settings
are
read
and
applied
only
while
powering
‐
on.
Table
2.3.
RS
‐
485/422
(4
‐
wire)
Signals
and
their
implementations
with
the
RS
‐
232/485
RF
Modem
DB-9 Pin
RS-485/422
Name
Description
Implementation
2 T-
(TA)
Transmit Negative
Data Line
Serial data sent from the RS-232/485 RF Modem
3 R-
(RA)
Receive Negative
Data Line
Serial data received by the RS-232/485 RF Modem
5 GND Signal
Ground
Ground
7 R+
(RB)
Receive Positive
Data Line
Serial data received by the RS-232/485 RF Modem
8 T+
(TB)
Transmit Positive
Data Line
Serial data sent from the RS-232/485 RF Modem
9 PWR Power
Optional power input that is connected internally
to the front power connector
1, 4, 6
not used
Wiring Diagram: RS-485 (4-wire) Half-Duplex
Figure
2.13.
RS
‐
232/485
RF
Modem
in
an
RS
‐
485
(4
‐
wire)
environment