>The UPS in our machine room provides a pair of wires which are an open 
>circuit when on line power and a closed circuit when on battery power.  I'd 
>like to detect this on a NetBSD/i386 box so sysadmins can be notified via 
>pager when we go onto UPS.  I'd prefer if it could be detected on two 
>different boxes for failover, but one box would work.
>
>Does anyone have any suggestions for how this could be done?

off the top of my head (upon which i am not wearing any sort of
electrical engineering hat), i'd say that the closed circuit could be
used to drive a relay that would connect the...uh...ctr line to the
dcd line on a serial port.  or something like that.

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