UPS & AS/400 talking to each other

Somewhat related to my last post on SPCN...

I noticed that my QUPSDLYTIM system value is set to *CALC.  How does the
AS/400 know how much juice is left to be able to determine whether it
needs to start shutting down?  Is there another cable that allows the
UPS and AS/400 to communicate this information?  I don't think our UPS's
have that, or if they do, they were never set up to do this.  If a comm
cable is required, then what is the effect of the *CALC setting?

Background for all this:  Last night, one of our branches cut power to
the building to install a new A/C unit (unbeknownst to us), relying on
the UPS to keep all of the computer equipment up for the "short" time
that the electricity was going to kept off.  I was told by the branch
manager that the AS/400 lost power immediately after the building power
was turned off.  While the building power was off, we powered the AS/400
back up, so this is how I know that the AS/400 was attached to the UPS.
The IPL was proceeding when the UPS got completely drained 15 minutes
later and then all equipment on the UPS went down.  Main power was
restored shortly thereafter, the AS/400 IPL'd normally (!), got a signon
screen within 20 minutes (a normal IPL for this box), nothing "damaged"
as far as I could tell.

Lessons learned:  Don't power the AS/400 back up until after main power
was restored.  WHAT THE @#%* WAS I THINKING?

Dan Bale
IT - AS/400
Handleman Company
248-362-4400  Ext. 4952
D.Bale@Handleman.com