OPTI-UPS DS160KD33 - Manual (Page 74)

8-1
8. REDUNDANCY
Redundancy can be roughly divided in two types: serial (hot standby) redundancy
and parallel (active) redundancy. DS-C33 series adopts mainly the serial
redundancy.
8.1. Serial Redundancy
ONE TO ONE SERIAL REDUNDANCY
The serial (hot standby) redundancy consist of two UPS with one UPS’s (UPS1)
connect to the reserve/bypass input of the other UPS (UPS2). See in the above
figure.