D-subminiature (D-sub) connectors transmit bus signals, data, and currents between equipment and devices. Also known as DB connectors, they make cable-to-board connections and communicate non-complex signals in industrial applications, such as computer systems, testing and measuring instruments, and medical equipment. They have two or more rows of pins or sockets, use set screws to attach connectors securely, and have a D-shaped metal shroud surrounding their contacts that ensures they plug in correctly and prevent electromagnetic interference.