CI-Ready indicates that the products are equipped with connection like RS-232, Flasher Out, IR Receiver in, DC-Trigger and similar used especially in the Custom Installation area. The RS232 for example is a communication port direct to the micro processor of the device. It is possible to control the component and get status feedback via this connection without any visual contact and even offers a way to update the system software if needed. Marantz products have dedicated remote codes and RS232 codes for any function including discrete power on / off.