NCR S26 - Manual (Page 148)

SCSI Channel Configurations
D-8 Hot Plug Backplane
Connect the second set pins for both jumpers J3 and J4 as shown in the figure
below.
Figure D-4. J3 and J4 Jumper Settings
J3 J4
The table below lists the terminator settings for the single-channel
configuration.
Table D-1. Terminator Settings for Single-Channel Configuration
Terminator Setting
With External Device
RA1, RA2, RA3
RA4, RA5, RA6 Removed
Removed (see note)
Without External Device
RA1, RA2, RA3
RA4, RA5, RA6 Installed
Removed
Note: For configurations with external device, terminate the signal at the
external device. Also, be sure the terminator switches are set to the left
(combine) position when installing a single-channel configuration.