Patent ID: 7131028

Claim:
An interconnect system for connecting at least two drawers of a redundant system, each drawer containing a redundant node, the interconnect system comprising: a first signal source and a first signal preventer operatively associated with a first drawer of the two drawers, the first signal source connected to a first processor in the first drawer and to a first signal terminal of the first drawer, and the first signal preventer connected to a first preventer terminal of the first drawer; a first connection interface connected to the first-drawer, comprising the first signal terminal, the first preventer terminal, and a first plurality of terminals connected to a redundant node of the first drawer; a second signal source and a second signal preventer operatively associated with a second drawer of the two drawers, the second signal source connected to a second processor in the second drawer and to a second signal terminal of the second drawer, and the second signal preventer connected to a second preventer terminal of the second drawer; a second connection interface connected to the second drawer, comprising the second signal terminal, the second preventer terminal, and a second plurality of terminals connected to a redundant node of the second drawer; and an electrical connector connecting the first connection interface to the second connection interface, whereby the first signal terminal is connected to the second preventer terminal, the second signal terminal is connected to the first preventer terminal, and the first plurality of terminals is connected to the second plurality of terminals; wherein the first signal source comprises a connection to a first voltage source through a first resistor and the second signal preventer comprises a connection to an electrical ground; wherein making an electrical connection between the first signal terminal and the second preventer terminal causes: a first electric current to flow through the first resistor from the first signal source to the second signal preventer; and a first voltage state at the first signal terminal indicating that redundant operation is available; and wherein breaking an electrical connection between the first signal terminal and the second preventer terminal causes: a second voltage state at the first signal terminal, different from the first voltage state and indicating that redundant operation is not available.