From: Mister Coffee (live4java@stormcenter.net)
Date: Wed Jun 23 2004 - 14:02:47 EDT
On Wed, Jun 23, 2004 at 08:58:38AM -0500, Ng, Kenneth (US) wrote:
> Safe is tricky. Electronic door locks are supposed to fail open in case of
> fire or power failure.
>
That depends on the specific type of lock. Yes, many of them do fail-unlocked in case of power failure. But many of them, particularly in Exterior Facing situations will fail locked, but have a physical "safety bar" release on the inside. That solves the safety needs.
Garage doors, gates, etc, are a different animal. Most electric garage doors I've encountered (and gates) can't be opened during a powerfailure without either physically forcing the device, or entering the garage and pulling a manual release lever.
My curiosity here isn't how they'll behave in the case of power outage, but what happens when you overload the receiver's front end with 100+ * normal signal. Do they blow chunks and open? Simply reset and go silent for a while? Or make a premature trip to Silicon Heaven.
Cheers,
L4J
> -----Original Message-----
> From: Mister Coffee [mailto:live4java@stormcenter.net]
> Sent: Friday, June 18, 2004 12:38 PM
> To: Richard Rager
> Cc: Amit Deshmukh; pen-test@securityfocus.com
> Subject: Re: RF code scanners
>
>
> On Thu, Jun 17, 2004 at 05:19:09PM -0600, Richard Rager wrote:
> > On Thu, 17 Jun 2004, Mister Coffee wrote:
> > > That depends on what you're trying to do.
> > > Side note:
> http://www.radioreference.com/modules.php?name=News&file=article&sid=467
> > > Openers are decidedly susceptible to jamming...
> > All FCC class C devices are susceptible to jamming. Look at wireless
> > alarm systems.
> >
>
> I wonder how many of these devices are designed to "Fail Open" when their
> receivers are overwhelmed. I don't imagine it would take much power to
> completely overload the front end of most garage door openers and the like.
>
> The "safe" way would be to "fail closed" of course, but we all know how
> security conscious most of the manufacturers out there are.
>
> Cheers,
> L4J
>
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