Abstract: An interface adapter enables a replacement controller to be mechanically received in a housing configured for an older model controller having a larger volume. Moreover, the interface adapter enables terminals of the replacement controller having a first configuration to be connected to the contacts of a housing connecter having a second configuration configured to couple with contacts of the older model controller. The interface adapter includes a faceplate having a central aperture for receiving the replacement controller and a pair of sideboard printed circuit boards (PCBs) positioned perpendicular to a surface of the faceplate in spaced parallel relation on opposite sides of the central receiving aperture. A main PCB is electrically and mechanically connected between the sideboard PCBs. The main PCB and the sideboard PCBs have contacts adjacent their ends opposite the faceplate.