I bought the 15-1994 today and I can't get it to work with my JVC 511 DVD player, my Kenwood VR-357 receiver and my Kenwood 223M 200 cd changer. I tried all the codes in the book and some listed on this site but no luck. Do I have to program this in for each unit, or am I just missing something? Thanks in advance for any help you might give.