APC UPS control system Troubleshooting Serial Line communications

Expected apctest Signals for a BackUPS Pro:

If you have conﬁgured yourUPS 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 p owerfails

and additionally CD when the batteries are low.

Troubleshooting Serial Line communications

The most frequentlyencountered problem with voltage-signalling UPSes (e.g.

BackUPS 650) is that you have incorrectlyspeciﬁed which cableis 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 haveestablished 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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