I've read the posts about similar issues with these two components. In my case, the SAT button is showing on the 2100, but it still will not work with the A55. I've tried assigning codes, learning, and searching for codes, but nothing has worked. I have also seen reference to switching the A55 from RF to IR. I just got through to Sony tech and they said after switching the A55 to IR everything should work fine. Other than this issue, the 2100 works great and was able to learn all functions for my Boston Acoustics DT7000 Home Theater.