A physical implementation of the matrix routing concept, which serves as an alternative to using patch cords to establish signal routing in modular synthesizer and semi-modular models. In a pin matrix, all signals are brought to a set of horizontal and vertical bars mounted behind a grid of holes. Signal outputs are connected to the horizontal bars and inputs are connected to the vertical bars (or vice versa). Inserting a metal pin in a hole establishes a contact between a horizontal bar and a vertical bar, hence establishing a routing.Synths that have used a pin matrix include the EMS VCS3 and the ARP 2500. The pin matrix makes for a much more tidy front panel than the traditional arrangement of patch jacks and cords (which tends to result in patch cords hanging in front of the knobs that