Serial Ports - Siemens RUGGEDCOM RX1400 Installation Manual

RUGGEDCOM RX1400
Installation Guide
Section 3.3

Serial Ports

The RX1400 supports two serial ports with DB9 connectors, which can be run in RS232, RS485 or RS422 mode.
For technical specifications, refer to
The following is the pin-out description for DB9 serial ports:
Serial DB9 Port
Figure 15: Serial DB9 Port Pin Configuration
a
In RS232 DCE mode, ports transmit to DTE devices on pin 2 and receive from DTE on pin 3.
Each RS485 port can communicate with multiple RS485 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:
• 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.
The following shows the recommended RS485 wiring.
Serial Ports
Section 4.4, "Serial Port
5 1
9 6
Specifications".
Pin
RS232 DCE
1 Reserved (Do Not Connect)
a
2 TX
a
3 RX
4 Reserved (Do Not Connect)
5 Common (Isolated) Ground
6 Reserved (Do Not Connect)
7 CTS
8 RTS
9 Reserved (Do Not Connect)
Shield Chassis Ground
Chapter 3
Communication Ports
Mode
RS422 RS485
TX- TX-/RX-
RX-
RX+
TX+ TX+/RX+
19