In the mid 90s I had (and still have at home) a HP 715 workstation.
after a heavy corruption due to power shortage I had a backups PSU to connect to (just for the AC) but no one would pay for more...
So I tried to figure out a workaround, after working out I had 10 minutes to shutdown the station, I came up writing a script for the cron which pinged my pc every 4 minutes and in case of a failure would do a shutdown... Not as elegant as a real software and port connection, but better than nothing...