[K12OSN] OT: Hardware Hacking: Share one UPS between two

Julius Szelagiewicz julius at turtle.com
Tue Dec 20 19:49:54 UTC 2005

> On Sun, 2005-12-18 at 12:07, Peter Hartmann wrote:
>> I'm looking to share an APC UPS between to computers with USB in a DIY
>> fashion. Can't I just splice 2 A male connectors (leaving the 5v +
>> unconnected) with a female A connector? To be more specific I mean to
>> connect all the pin 2s to each other; all the pin 3s to each other;
>> all the pin 4's to each other and leave all the pin 1s unconnected.
>> I'm trying the UPS to signal the shutdown without networking because
>> one computer is in the dmz and the other is the LTSP server.
> That might work with a standard serial port where the ups software
> just watched the CD lead to become active but I don't think
> you can do it with USB.  Maybe you could just connect to your
> inside machine and add something in the shutdown sequence to
> ssh a shutdown command to the dmz box.
I've been using the APC software - PowerChute on HP-UX computers and it
allows you to connect the UPS to one of the servers over serial port and
the other servers communicate with the UPS via TCP/IP. That setup works
very well despite being rather old. All the servers get information about
power events and you can view the UPS interface from all of them. Easoer
than hacking hardware. julius

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