Abstract: A programmable switch for broadband signals having a modular design in which input cards, bridging cards and output cards are interconnected through a common backplane to form a switching matrix having a Clos architecture. All connections between cards are made through the backplane to decrease the complexity of the switch and are arranged to minimize the length of signal traces to minimize signal loss. The backplane is unique in that it is configured with venting holes to facilitate the flow of cooling air therethrough. All modules, including input cards, output cards and bridge cards are hot swappable.