Non-blocking concentrator

The present invention provides a single stage crossbar and a controller for controlling the crossbar that provides a capacity for "wide-sense non-blocking" connection of input signals to outputs that exceeds the number of outputs to which a given input is connected. Thus, the capacity of the crossbar is increased using a smaller number of crosspoints in a single stage than was available in the prior art. In one aspect, the present invention is an apparatus for connecting a signal on one of a plurality of inputs to a non-busy one of a plurality of outputs, comprising a plurality of controllable switches arranged so that each input is connectable to at least an integer q outputs and so that no two inputs share more than an integer c outputs. The invention further comprises a controller for controlling the controllable switches to connect the signal to a non-busy output so that no more than an integer f outputs that are connectable to any input become busy, where f is less than q.