This cable can only be used on voltage-signalling UPSes, and provides the On Battery signal as well as kill UPS power (and may be Low Battery signal).
| UPS Signal Name |
DB-9 Male (UPS end) |
DB-9 Female (PC end) |
PC Signal Name |
| Shutdown | 1 | 4 | DTR |
| AC Fail | 2 | 8 | CTS |
| Common | 4,9 | 5 | GND |
APC Part# - 940-0020B (investigated by apcupsd team)
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)
Note: sides swapped.
Compatible with Back-UPS BK500MC, BK300C, BK650MC, Smart-UPS VS SUVS420, SUVS650, SUVS1000, SUVS1400
Full scheme of 940-0020C isnt yet known.
APC Part# - 940-0020C (investigated by apcupsd team)
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
Our users reports that the 20C is designed to mimic a mouse movement when it received an on battery signal from the Back-UPS. Therefore the computer will wake up and shutdown properly. The 20B cable does not have this functionality.
Full scheme of 940-0020C.
APC Part# - 940-0020C (Scheme is redrawn with the destruction of the gray cable)
Signal Computer UPS
DB9F DB9M
RI 9 --*
|
CTS 8 --*-------------------- 2 On Battery
DTR 4 ----------------------- 1 Kill power
GND 5 ----------------------- 4 Ground
RTS 7 --*-[47K]-*-----[47K]-- 5 Low Battery
E| |
\| B |
C |-----*
DCD 1 ---/| PNP 2n3906
Compatible with Back-UPS Pro PNP BP280PNP, BP420PNP, BP650PNP, BP280C, BP420C, BP650C, BP1000, BP1100, BP1400
correct
incorrect