Siemens RUGGEDCOM RX1400 Installation Manual page 41

Communication Ports
4.3 Serial Ports
The following is the pin-out description for DB9 serial ports:
Serial DB9 Port
Figure 4.3
a
In RS-232 mode, ports transmit to DTE (Data Terminal Equipment) devices on pin 2 and receive from
DTE devices on pin 3.
Each RS-485 port can communicate with multiple RS-485 devices by wiring devices
together 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:
•
•
•
•
•
•
The following shows the recommended RS485 wiring.
32
5 1
9 6
Serial DB9 Port Pin Configuration
Pin
RS-232
1
2 RX
3 TX
4
5
6
7 RTS
8 CTS
9
Shield
To minimize the effects of ambient electrical noise, use shielded cabling.
The correct polarity must be observed throughout a single sequence or ring.
The number of devices wired should not exceed 32, and total distance should be
less than 1219 m (4000 ft) at 100 kbps.
The Common terminals should be connected to the common wire inside the
shield.
The shield should be connected to earth ground at a single point to avoid loop
currents.
The twisted pair should be terminated at each end of the chain.
RS-422
Reserved (Do Not Connect)
a
a
Reserved (Do Not Connect)
Common (Isolated) Ground
Reserved (Do Not Connect)
Reserved (Do Not Connect)
Chassis Ground
Mode
RX-
TX-
TX+
RX+
Installation Manual, 09/2019, C79000-G8976-1103-13
RS-485
RX-/TX-
RX+/TX+
RUGGEDCOM RX1400