Abstract: Logic fencing circuit and method are provided for increasing system protection at a multiprocessor system interface so that spurious noise (e.g., attributable to an electrostatic discharge through a signal cable) is more reliably isolated from an active portion of the processing system. The noise fencing circuit, which is responsive to a fence control signal, includes logic circuitry for attenuating a received noise signal by constraining the noise signal to a magnitude less than or equal to the voltage level of a system power supply. The attenuating circuitry outputs an attenuated noise signal to a signal fence circuit which, when enabled by the fence control signal, outputs a substantially constant isolation signal in response to a received, attenuated noise signal. A logically staged fencing method is also set forth.

Abstract: A static dissipative electrical cable which eliminates the build-up of triboelectric charging by having a carbon loaded outer jacket which is a semiconductor for draining off triboelectric charges. In one embodiment, the jacket material is a 1 megohm/ft semiconductive extrudable Teflon polyfluorinated alkoxy (PFA) resin static-dissipative polymer of low carbon-black loading (3-4% by weight) having very stable electrical/mechanical properties against temperature excursions, thermal/environmental shock and aging. The cable is designed with a double-clad aluminum/mylar foil shield that allows electrical commoning between inner and outer clads of the foil and control of the interface between semi-conductive static-dissipative jacket and the foil shield to yield a jacket-to-ground wire resistance value between 100 kilo-ohms and 50 megohms.