If your remote has the microphone button these are the instructions to follow.

Program your Comcast XR-15 remote using a ZVOX code:

1. Turn on the ZVOX system

2. Press and hold the Mute and Xfinity buttons on the remote until the status LED at the top of the remote changes from red to green.

3. Type in 33913 using the number buttons. Additional codes may be found in the remote manual.

Most likely code

Other ZVOX codes to try
31943, 32334, 32332

4.  If the code is entered correctly, the status LED will flash green twice. If the status LED blinks red, then green the code was not entered correctly. Check that you are entering the correct code and try again.

5.  Use the remote to operate your Audio/Other (use Power, VOL, etc.)

6.  If these steps don’t work, try another ZVOX code and repeat the above steps.