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RS-485 (4-wire) and RS-422 Operation
9XTend-PKG-R RS-232/485 RF Modem User Guide
18
RS-485 (4-wire) and RS-422 Operation
DIP switch settings and pin signals
The following table shows the RS-485/422 (4-wire) Signals and their implementations on the XTend RF Modem.
RS-485 (2-wire) Half-duplex DIP Switch Settings
Pins used on the female RS-232 (DB-9) Serial Connector
RS-485 (2-wire) w/ Termination (optional)
Termination
is
the
120
resistor
between
T+
and
T
‐
.
DIP
Switch
settings
are
read
and
applied
only
while
powering
‐
on.
DB-9 Pin RS-485/422 Name Description
Implementation
2
T- (TA)
Transmit Negative Data
Line
Serial data sent from the RF modem
3
R- (RA)
Receive Negative Data
Line
Serial data received by the RF modem
5
GND
Signal Ground
Ground
7
R+ (RB)
Receive Positive Data
Line
Serial data received by the RF modem
8
T+ (TB)
Transmit Positive Data
Line
Serial data sent from the RF modem
9
PWR
Power
Optional power input that is connected internally to the front power
connector
1, 4, 6
not used