How to use your Comcast remote control with an IR Extender/Receiver
An IR Extender or IR Receiver (included with your digital adapter equipment) lets you place your cable box or digital adapter (DTA) out of sight, but still use your remote control to change channels on the cable box. Simply connect the IR Extender to the IR In input on the back of the cable box and position the receiving end of the IR Extender in plain sight of the remote.
An important note about IR Extenders: With some cable boxes, connecting the IR Extender disables the RF input on the front of the actual cable box. So, if you are not using the IR Extender, be sure to disconnect it from the cable box.