Rockwell Automation 1775-KA PLC-3 Communication Adapter Module User Manual - Manual (Page 56)

Data Highway Communication
Chapter 3
3Ć11
PLC–4 Stations
To read or write to a PLC–4 station, you can send either protected or
unprotected commands.
Switches 2 and 3 (on the second row of switches) at the 1773–KA module
specify whether the PLC–4 station will accept unprotected and protected
commands (respectively) through the Data Highway port of the 1773–KA
module.
Switches 1 and 3 (on the third row of switches) at the 1773–Ka module
specify whether the PLC–4 station will accept protected and unprotected
commands (respectively) through the RS–232–C port of the 1773–KA
module. In all cases, if the switch is set to the closed position, the module
will accept that type of command.