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RS-485 (2-wire) operation
9XTend-PKG-R RS-232/485 RF Modem User Guide
17
Note
Refer to Figure 3-15 and Figure 3-16 for the RJ-45 connector pin designations used in RS-485/422
environments.
The following table shows RS-485 (2-wire half-duplex) signals and their implementations on the XTend RF Modem.
Wiring diagram
The following diagram shows the XTend RF Modem in an RS-485 (2-wire) half-duplex environment.
t
Termination
is
the
120
resistor
between
T+
and
T
‐
.
DIP
Switch
settings
are
read
and
applied
only
while
powering
‐
on.
DB-9 Pin
RS-485 Name
Description
Implementation
2
T/R- (TRA)
Negative Data
Line
Transmit serial data to and from the RF modem
5
GND
Ground Signal
Ground
8
T/R+ (TRB)
Positive Data Line Transmit serial data to and from the RF modem
9
PWR
Power
Optional power input that is connected internally
to the front power connector
1, 3, 4, 6, 7
not used