1. Introduction

This HOWTO covers connecting a UPS to a PC running Linux. The idea is to connect the two in such a way that Linux can shutdown cleanly when the power goes out. To a large extent this document is reduntant, because all the basic info is contained in the powerd man page that comes with the SysVinit package. None the less, there seems to periodically be alot of discussion on the net regarding connecting Linux PCs to UPSs (and the versions of Linux that I installed didn't come with a powerd man page). I figured having a HOWTO would be a good idea because:

• A second source of information might help to understand how to connect Linux to a UPS, even if it's just the same information written differently.
• The HOWTO can serve as a repository for UPS specific data.
• The HOWTO contains additional details that aren't in the powerd man page.

None the less, this does not replace the powerd man page. Hopefully, after reading both, people will be able to deal with UPSs.

1.1 Contributors

I am forever indebted to those from whom I've received help, suggestions, and UPS specific data. The list includes, in order of appearance in this document:

• Miquel van Smoorenburg (miquels@cistron.nl.mugnet.org)
• Danny ter Haar (danny@caution.cistron.nl.mugnet.org)
• Hennus Bergman (hennus@sky.nl.mugnet.org)
• Tom Webster (webster@kaiwan.com)
• Marek Michalkiewicz (ind43@sun1000.ci.pwr.wroc.pl)
• Christian G. Holtje (docwhat@uiuc.edu)
• Ben Galliart (bgallia@orion.it.luc.edu)
• Lam Dang (angit@netcom.com)

1.2 Important disclaimer

I really can't guarantee that any of this will work for you. Connecting a UPS to a computer can be a tricky business. One or the other or both might burn out, blow up, catch fire, or start World War Three. Furthermore, I only have direct experience with the Advice 1200 A UPS, and I didn't have to make a cable. So, BE CAREFUL. GATHER ALL INFORMATION YOU CAN ON YOUR UPS. THINK FIRST. DON'T IMPLICITLY TRUST ANYTHING YOU READ HERE.

On the other hand, I managed to get everything working with my UPSes, without much information from the manufacturer, and without burning out anything, so it is possible.

1.3 Other documents

This document does not cover the general features and capabilities of UPSs. For this type of information, you might turn to the UPS.faq, which is available via anonymous FTP from navigator.jpl.nasa.gov (128.149.23.82) in pub/doc/faq/UPS.faq, and can probably be found somewhere on rtfm.mit.edu. It is maintained by Nick Christenson (npc@minotaur.jpl.nasa.gov). In email to him, he'd like that you put UPS or UPS FAQ or something along these lines in the Subject line of the message.