nanog mailing list archives
Re: First real-world SCADA attack in US
From: Jay Ashworth <jra () baylink com>
Date: Tue, 22 Nov 2011 18:14:54 -0500 (EST)
----- Original Message -----
From: "Matthew Kaufman" <matthew () matthew at>
Indeed. All solid-state controllers, microprocessor or not, are required to have a completely independent conflict monitor that watches the actual HV outputs to the lamps and, in the event of a fault, uses electromechanical relays to disconnect the controller and connect the reds to a separate flasher circuit. The people building these things and writing the requirements do understand the consequences of failure.
If you mean "an independent conflict monitor which, *in the event there is NO discernable fault*, *connects* the controller to the lamp outputs... so that in the event the monitor itself fails, gravity or springs will return those outputs to the flasher circuit", than I'll accept that latter assertion. Cheers, -- jra -- Jay R. Ashworth Baylink jra () baylink com Designer The Things I Think RFC 2100 Ashworth & Associates http://baylink.pitas.com 2000 Land Rover DII St Petersburg FL USA http://photo.imageinc.us +1 727 647 1274
Current thread:
- Re: First real-world SCADA attack in US, (continued)
- Re: First real-world SCADA attack in US andrew.wallace (Nov 22)
- Re: First real-world SCADA attack in US Michael Painter (Nov 22)
- Re: First real-world SCADA attack in US Joe Hamelin (Nov 22)
- Re: First real-world SCADA attack in US Mike Andrews (Nov 23)
- Re: First real-world SCADA attack in US Valdis . Kletnieks (Nov 22)
- Re: First real-world SCADA attack in US Steven Bellovin (Nov 22)
- Re: First real-world SCADA attack in US Steven Bellovin (Nov 22)
- Re: First real-world SCADA attack in US Michael Painter (Nov 22)
- Re: First real-world SCADA attack in US Ryan Pavely (Nov 22)
- Re: First real-world SCADA attack in US andrew.wallace (Nov 22)
- Re: First real-world SCADA attack in US Jay Ashworth (Nov 22)
- Re: First real-world SCADA attack in US Brett Frankenberger (Nov 22)
- Re: First real-world SCADA attack in US Jimmy Hess (Nov 22)
- Re: First real-world SCADA attack in US Jay Ashworth (Nov 22)
- Re: First real-world SCADA attack in US Valdis . Kletnieks (Nov 22)