System for switching from working units to stand-by units

Claim 1

A switching system for switching between at least one unit in a working state and at least one stand-by unit in a stand-by state, said system selectively operating each of the at least one stand-by unit as one of an individual stand-by unit and a common stand-by unit accessed by an individual switching unit, comprising: input/output lines for transmitting data; individual units, each comprising one from among the individual stand-by unit and the individual switching unit, each individual stand-by unit and each individual switching unit including first switches connected to said input/output lines; working units, each including second switches operatively connected to said input/output lines, each of said working units corresponding to one of said individual units in a pair arrangement; failure detection means for providing fault detection signals indicating faults in said working units; and a control unit, operatively connected to said working and individual units and said failure detection means, for controlling switching between one of said working units and the corresponding one of said individual units based on the fault detection signals from said failure detection means, upon occurrence of a failure in the one of said working units, said second switches disconnecting said input/output lines from the one of said working units, said first switches connecting said input/output lines to the corresponding one of said individual units and, when the corresponding one of said individual units is the individual switching unit, said first switches connecting said input/output lines to the common stand-by unit.