LRS-455-EU Data Transceiver Users Manual
LUM0032AA Rev A
Version 1.0
25
RS-422
AND
RS-485
F
ULL
D
UPLEX
P
IN
-O
UTS
Function
Bare Board Pin Number
DE-9 Pin Number
RX+
7
3
RX-
9
7
TX+
5
2
TX-
10
8
Signal Ground
4 or 6
5
RS-485
H
ALF
D
UPLEX
P
IN
-O
UTS
Function
Bare Board Pin Number
DE-9 Pin Number
Wire to both pins for Bus +
Short 5 and 7
Short 2 and 3
Wire to both pins for Bus -
Short 9 and 10
Short 7 and 8
Signal Ground
4 or 6
5
RS232 Pin Assignments
Pin
Assignment
Signal
Definition
1
CD
Carrier Detect
Output Used to show an RF connection between transceivers.
2
TX
Transmit Data
Output Used to transmit data bits serially from the transceivers to the
system device.
3
RX
Receive Data
Input
Used to receive data bits serially from the system device
connected to the transceivers.
4
DTR Data Terminal Ready Input
Used only in transceivers in Point-to-Point Slave/Master
switchable mode or for DTR Connect.
5
GND Ground
Signal return for all signal lines shared with Pin 9.
6
DSR Data Set Ready
Output Always high when the radio is powered from the 2.5mm
power connector. Indicated power is on to the radio. Also,
this pin can be used for +12Volts when powering the
transceivers directly through the RS-232 port.
Note:
This is not used on the OEM module.
7
RTS Request to Send
Input
The transceiver does not recognize RTS for flow control. RTS
is used as a control line in RTS/CTS mode.
8
CTS Clear to Send
Output This signal is used to tell the system device connected to the
transceiver that the transceiver is ready to receive data.
When asserted, the transceiver will accept data, when
deasserted the transceiver will not accept data. This should
always be used for data rates above 38.4KB or there will be a
risk of lost data if an RF link is not very robust.
9
GND Ground
Signal return for all signal lines shared with Pin 5.
