Rockwell Automation 1770-KF2 Data Highway or Highway Plus Interface Module User Manual - Manual (Page 27)

Installation
Chapter 3
3-3
Switch 3 determines whether the asynchronous port of the KF2 module
can detect duplicate messages transmitted to it.
If You Want Your Module to: Set Switch 3:
Detect and Ignore Duplicate Messages ON
Accept All Messages Regardless of Duplication OFF
Switch 4 determines whether the module uses and recognizes the
following handshaking signals: data set ready, request to send, clear to
send, data carrier detect, and data terminal ready.
If You Want the Module’s Asynchronous Port to: Set Switch 4:
Use Handshaking Signals ON
Ignore Handshaking Signals OFF
Important: If you select half-duplex, the KF2 uses handshaking signals
even if Switch 4 is set OFF.
Station Number
Switch Assemblies SW-2, SW-3, and SW-4 are for setting the network
station number of the KF2 module. For the Data Highway, the station
number is a 3-digit octal number that identifies the KF2 module as a
unique station. Valid station numbers for the KF2 module in Data
Highway mode are 010 to 077 and 110 to 376 octal. For a PCL, the
station number is 2 digits; set both switches in SW-2 OFF. Valid station
numbers for the KF2 in PCL mode are 00 to 77 octal.
Figure 3.2 shows an example of how to set the KF2 station number to
037 octal. The switches in Assembly SW-2 set the first (left-most) digit
of the station number; Switch Assembly SW-3 sets the middle digit; and
Switch Assembly SW-4 sets the last (right-most) digit.
Station numbers play an important part in the polling scheme described in
Chapter 2. They can also influence the order in which mastership is
transferred between network stations. Therefore, we recommend that you
always begin numbering stations with the lowest possible number and
continue with the next available number in sequence.