APC UPS control system - Manual (Page 161)

Expected apctest Signals for a BackUPS Pro:
If you have configured your UPS as:
UPSTYPE backupspro
UPSCABLE APC_940_0095A
or APC_940_0095C
here are the typical signals you would expect to see in the output from the
various tests of apctest:
Test 1 normal: RTS not set
Test 2 no serial cable: not important
Test 3 no AC power: RNG
Test 4 batteries exhausted: RNG and CD
Note: RTS should never be set in any of the tests as it is the killpower
signal. What is important is the appearance of RNG when the power fails
and additionally CD when the batteries are low.
Troubleshooting Serial Line communications
Determining Which Voltage-Signaling Cable You Have
The most frequently encountered problem with voltage-signalling UPSes (e.g.
BackUPS 650) is that you have incorrectly specified which cable is being used.
All cables furnished by APC have the cable number stamped on the side of
the computer connector end of the cable. Using this number with apcupsd
will normally work fine. If you do not know what cable you have, you can
use the apctest program to determine the type of the cable.
For simple signaling UPSes, you should not use simple in the cable specifi-
cation (i.e. UPSCABLE simple) unless you have made the cable yourself
according to the wiring diagram given in the cables chapter of this manual.
Once you have established serial communications
Once you have established that apcupsd can talk to the UPS over the serial
part, go do the series of functional tests described in the main Testing (see
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