Patent ID: 7271991

Claim:
A circuit for interconnecting low voltage signals and providing over voltage protection, the circuit comprising, a) a plurality of input ports for receiving low voltage signals, b) a plurality of output ports for transmitting the low voltage signals received at the input ports, c) each of said input ports being connected to a corresponding output port by a separate parallel array of signal conductive paths, each parallel array of signal conductive paths comprising a signal ground path connected to a common ground d) a common uni-direetional voltage limiting device, e) a first ground rectifying diode having an anode connection to the cathode of said common uni-directional voltage limiting device, and a cathode connected to the common ground, f) a second ground rectifying diode having a cathode connection to the anode of said common unidirectional voltage limiting device, and an anode connected to the common ground, g) a plurality of first and second diode pairs, wherein each first and second diode pair is associated with one of the signal conductive paths between said input and output ports, h) wherein each of the signal conductive paths between said input and output ports is coupled by a conductive path to a junction with the anode of said first diode of its associated diode pair and the cathode of said second diode of its associated diode pair, i) wherein the cathodes of the first diodes are coupled to the anode of said common uni-directional voltage limiting device, and the anodes of the second diodes are coupled to the cathode of said common unidirectional voltage limiting device, j) whereby the rectifying diodes direct current arising from an over voltage transient between a signal input and output port to flow through one of said first and second diodes connected to the signal conductive path between the signal input and output port before reaching the common unidirectional voltage limiting device, the current continuing to flow through one of the first and second ground rectifying diodes before reaching the common ground, thereby isolating other signal conductive paths from the over voltage condition.