Rockwell Automation 1769-L23E-QB1B_L23E-QBFC1B_L23-QBFC1B CompactLogix Packaged Controllers Quick Start and User Manual - Manual (Page 167)

Publication IASIMP-QS010B-EN-P - October 2009 167
Network Communication Chapter 2
Determine Need for Isolator and Cable for Connection
Channel 0 on the CompactLogix controllers is fully isolated and does not need
a separate isolation device. Channel 1 on the 1769-L23-QBFC1B packaged
controller is not an isolated serial port.
You should consider installing an isolator in these situations:
• between the controller and modem or ASCII device.
• when connecting directly to the controller from a workstation.
An isolator that you might consider using is the 1761-NET-AIC interface
converter shown here.
1761-NET-AIC Interface Converter
User Communication with ASCII devices.
Use of this mode requires you to use ASCII instructions in your program to transmit data to and from ASCII
devices.
DH-485 Communicate with other DH-485 devices. This multi-master, token-passing network allows programming and
peer-to-peer messaging.
CompactLogix Serial Port Configuration
Mode Functions
Port 2: Mini-DIN 8 RS-232
DC Power Source Selector Switch
Terminals for External 24V DC
Power Supply
Baud Rate Selector Switch
Port 1: DB-9 RS-232, DTE