A switching network is used to switch and connect signals
. It is used to switch input signals to corresponding outputs in a completely transparent manner. A switching network consists of several interconnected matrices (switching multiples) of incoming and outgoing lines, which used to be interconnected via electromechanical contacts, but are now interconnected via electronic contacts. Typically, patch panels form the central switching unit of exchanges and PBXs
. The term patch panel has been superseded by the terms patch panel or patch field. All these patch panels are used to distribute and patch connections. In audio and television technology, one speaks of patch panels and crossbar distributors.