Patent ID: 6850517

Claim:
A high-capacity electronic switching system comprising: two or more first stage switch modules to each of which one or more subscriber terminals are connected and each of which executes signal switching for signals from/to the subscriber terminals; and a second stage switch module providing a communication path by receiving a signal outputted by one of the first stage switch modules via a first line, switching the signal, and outputting the signal to another one of the first stage switch modules via a second line, wherein: each of the first stage switch modules is connected to another one of the first stage switch modules via a special-purpose link for setting a communication link between the first stage switch modules, said special-purpose link separate and distinct from said communication path; and said switch system further comprising one or more central control units for controlling the first stage switch modules and the second stage switch module; wherein the central control units include one or more first central control units for controlling the first stage switch modules and a second central control unit for controlling the second stage switch module, and control information is communicated between the central control units via a control bus; and wherein the setting of the communication link via the special-purpose link is executed when an abnormal condition of the control bus has occurred and the control information communication between the central control units via the control bus is abnormal or impossible.