APC UPS control system - Manual (Page 145)

analysis) indicates that this cable under the right conditions may provide
the Low Battery signal. This is to be confirmed.
APC Part# - 940-0020B
Signal Computer UPS
DB9F DB9M
CTS 8 -------------------- 2 On Battery
DTR 4 -------------------- 1 Kill power
GND 5 ---------------*---- 4 Ground
|
--- *---- 9 Common
DCD 1 ----|///|----------- 5 Low Battery
|\\\|
RTS 7 ----|///| (probably a
--- semi-conductor)
Thanks to Lazar M. Fleysher.
940-0020C Cable Wiring:
This diagram is for informational purposes and may not be complete, we
don’t recommend that use it to build you build one yourself. This cable
can only be used on voltage-signalling UPSes, and provides the On Battery
signal, the Low Battery signal as well as kill UPS power. In apcupsd versions
3.8.2 and prior, please set your UPSCABLE to 940-0020B. In version 3.8.3
and later, you may specify the cable as 940-0020C. Please note that this
diagram may not be accurate.
APC Part# - 940-0020C
Signal Computer UPS
DB9F DB9M
CTS 8 -------------------- 2 On Battery
DTR 4 -------------------- 1 Kill power
GND 5 ---------------*---- 4 Ground
|
*----
9 Common
RTS 7 -----[ 93.5K ohm ]----- 5 Low Battery
or semi-conductor
144