Welcome to the home of ShutDown/2, the utility that allows you to attach an UPS (Uninterruptable Power Supply) to your PC's serial or parallel ports.
In order to use that function, you need to create a plug that connects your PC's serial or parallel port with the control lines of your UPS. Just be sure not to exceed the power requirements (e.g. 0 to 5 V for parallel and -15 to +15 V for serial ports) to avoid damage to your PC. Though not intensively tested, you may even continue to use that port for your modem or printer.
This program was developped in 1993 (or so) for a special hardware box that attached between the PC and the UPS, but it shouldn't be a problem to directly connect the PC to the UPS.
I provide that program here in case you might find it useful and too much time it being in a drawer got wasted yet. If you do I would be pleased to get some feedback, with feedback I might even make changes according to your requirements or wishes.