Matrix Switch was an electronic switch with multiple input and output ports that could be controlled from a keypad or some other front-panel switching facility. Matrix switches were used to allow multiple stations to share a group of peripherals such as printers, modems, Small Computer System Interface (SCSI) devices, or other serial or parallel devices.

The term “matrix switch” comes from the mathematical structure called a matrix, which is a two-dimensional structure with N rows and M columns representing N times M values. Likewise, a matrix switch with N input ports and M output ports has N times M switching possibilities. Typical configurations for matrix switches include 4 x 4 and 4 x 8.

Code-operated matrix switches can be operated by character codes embedded in the data stream sent from user workstations.

When printers started to include network interfaces this kind of equipment became obsolete.

ATM matrix switching

The term “matrix switching” also describes the switching technology at the center of an Asynchronous Transfer Mode (ATM) network that functions by supplying needed bandwidth for end-to-end sessions. ATM matrix switching avoids contention by end stations on the network.