Serial Rs232/Rs485/Rs422 Fiber Ports; Connecting Multiple Rs485 Devices - Siemens SIMATIC NET RUGGEDCOM RS920L Installation Manual

The following is the pin-out description for the RS232/RS485/RS422 RJ45 ports:
8
Figure 4.4
a
No internal termination is provided.
b
Connected internally.
c
Connected internally.
d
In RS232 mode, this pin enters a high impedance state. A DTE that asserts RTS will see CTS asserted,
although the device will not perform hardware flow control.
4.2.3

Serial RS232/RS485/RS422 Fiber Ports

The RS920L can be equipped with serial RS232/RS485/RS422 fiber ports. Each port
can be set individually through the RUGGEDCOM RS920L operating system to oper-
ate in RS232, RS485 or RS422 mode. For more information, refer to the RUGGED-
COM RS920L User Guide for the RS920L.
The following is the pin-out description for the RS232/RS485/RS422 fiber ports:
1
Figure 4.5
4.2.4

Connecting Multiple RS485 Devices

Each RS485 port can communicate with multiple RS485 devices by wiring devices to-
gether in sequence over a single twisted pair with transmit and receive signals on the
same two wires (half duplex). For reliable, continuous communication, adhere to the
following guidelines:
•
•
RUGGEDCOM RS920L
Installation Manual, 02/2020, C79000-G8976-1032-06
RS232/RS485/RS422 RJ45 Ser-
ial Console Port
RS232/RS485/RS422 Fiber Se-
rial Console Ports
To minimize the effects of ambient electrical noise, use shielded cabling.
The correct polarity must be observed throughout a single sequence or ring.
4.2.3 Serial RS232/RS485/RS422 Fiber Ports
1
2
Communication Ports
a
Pin Name
RS232 RS485
Mode Mode
b
1 DSR/RI
b
2 DCD
c
3 DTR
4 Common (Isolated) Ground
5 RX
6 TX TX/RX+
c d
7 CTS
c d
8 RTS TX/RX-
Shield Chassis Ground
Pin
1
2
RS422
Mode
RX-
RX+
TX+
TX-
Name
Rx
Tx
25