Many devices, such as printers, work with one or more removable unit. Often, the removable units have an electronic circuit that used to communicate with the device. It may be desirable to provide a replacement unit in these devices. The replacement unit must include an electronic circuit that is able to communicate with the original device. Disclosed is a method and apparatus where a replacement unit is provided with a new electronic circuit and a used electronic circuit. The new electronic circuit is electrically connected to the used electronic circuit and uses the used electronic circuit to facilitate communication with the host device.