Omron NT31 Operation Manuals page 135

Connecting to the Host's RS-422A/485 Port
124
[Setting the front switches]
I/O port selector switch
RS-232C
RS-422A
Section 5-2
@ Host link communication method
selection (selector switch)
Set this to "RS-422A".
@ Communication type setting (DIP SW3)
Set SW3 to "OFF".
(for "host link" communication)
@ Host link default value settings
(DIP SW4)
To effect the existing DIP switch settings,
set SW4 to "ON".
To effect the values set in the PC system
settings, set SW4 to "OFF".
Note
For CPUs manufactured before or during
June 1995 (lot No. jj65), the existing
DIP switch settings differ from the PC
system setting default values as follows.
- Existing DIP switch settings:
2400 bps, 1 stop bit, even parity, 7 bit
data length
- PC system setting default values:
9600 bps, 2 stop bits, even parity, 7 bit
data length
For CPUs manufactured from July 1995
onward (lot No. jj75), the stipulated
values in the DIP switch settings also
are 9600 bps and 2 stop bits.
@ Terminator setting (DIP SW6)
Set this switch to "ON".
(Set terminator "ON".)