Binding post

A binding post is a connector commonly used on electronic test equipment to terminate (attach) a single wire or test lead. They are also found on loudspeakers and audio amplifiers as well as other electrical equipment.A binding post contains a central threaded metal rod and a cap that screws down on that rod. The cap is commonly insulated with plastic and color-coded: red commonly means an active or positive terminal; black indicates an inactive (reference or return) or negative terminal; and green indicates an earth (ground) terminal.Commonly designed in a style called five-way or universal, such binding posts allow the connection of several different types of connections:

The binding post was a commercial invention of the General Radio Corporation.
 * Banana plugs, inserted into the open end of the binding post
 * Pin connectors, inserted into a hole drilled through the metal post and clamped by the screw-down portion of the binding post.
 * Bare wire inserted through the same hole and clamped, or
 * Wrapped around the metal post and clamped.
 * A lug terminal inserted around the metal post and clamped.