Apparatus for coupling a signal between a wiring and a device. Junction box mounting is popular in North America, whereas cavity mounting is popular in Europe and the Middle East. The apparatus includes an adapter and provides universal mounting for specialized faceplates which are designed and intended for junction box mounting. The adapter features clamps for gripping the inner surface of a wall cavity or sleeve and a plate for mounting an faceplate designed for junction box mounting. The plate has mounting points with a nominal center-to-center distance of 31/4 inches, corresponding to the requirements of junction box mounting.