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From: "Rashid Karimov." <rashid@haven.ios.com>
Message-Id: <199507071722.NAA23818@haven.ios.com>
Subject: Re: Using No-break Power Systems
To: mnewell@lupine.nsi.nasa.gov (Michael C. Newell)
Date: Fri, 7 Jul 1995 13:22:50 -0400 (EDT)
Cc: chuckr@Glue.umd.edu, FreeBSD-Questions@freefall.cdrom.com
In-Reply-To: <Pine.SUN.3.91.950707110514.26989R-100000@lupine.nsi.nasa.gov> from "Michael C. Newell" at Jul 7, 95 11:13:32 am
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		Hi there folx,

> 
> On Fri, 7 Jul 1995, Chuck Robey wrote:
> 
> > My new apartment comes with full amenities, including (what seems to be) 
> > daily short power interruptions, usually less than 1 minute in length.  I'd
> > like to get no-break power, something like an APC power system, just for 
> 
> I have a Tripp-Lite 500P 500 VA and a Tripp-Lite 450LAN (it's proclaimed
> to be "Internet Ready" on the box; this means it's got a telephone line
> 
> The thing that's missing from these guys is there's no test output that
> tells the system they are connected to the state of the power; hence
> there's no way for your system to gracefully shutdown once the unit
> reaches their limits.  In my case I have the same problem you do - short
> outages mainly caused by thunder storms; I was looking for a surge
> suppressor (those outlet strips are pretty useless) as well as a backup
> unit.  I had about 4 outages in one week so I decided to buy the backup
> units; since then (of course) no new outages occur. 

	Usually UPS'es come standard with DB-9 like socket , on
	which there are 2 or 3 pins ( TTL) which change the voltage
	on them during power failures - so it's pretty easy to analize
	the output from them via some simple program ( say using the
	pin which goes to 1 when there is problem as DCD, so you'll
	be able to open the port only when the power disapears) and
	take appropriate actions w/o wroting actual device driver :)
	Even dumb( back-up ) UPS often have this connectors.

	Rashid