I have an APC UPS with all my computer peripherals plugged into it. When I'm done using the computer, I'd like to be able to type "shutdown" or "init 0" and walk away from the machine, trusting that it will shut down cleanly and then signal the UPS to shut off power to all peripherals.
I understand that there is a "kill the power" signal that APC UPSes can be sent, and I have that working in the event of a power failure: apcupsd will shut down the computer and, at the last moment, tell the UPS to turn off. But this only works when running on battery.
When it gets that killpower signal while running on AC power, the UPS turns off for a few seconds, and then it turns right back on automatically. Is this expected behavior? Can it be disabled, so that the UPS stays off, even when there is AC power?