Tivo updated their systems I believe its for cetain cable box that this works:
Within the Tivo's multitude of menus under Remote Set Up I found ZVOX listed with codes: 2026, 2065, 2027. I followed their instructions regarding TIVO remote:
#1. "Hold down the TV POWER and Tivo buttons together for 5 seconds---until light at top center of remote remains on.
#2. Enter 4 digit code (I used 2026).
#3. Test the TV POWER button." This worked and I can now control Vol. Mute and Power for the ZVOX from my Tivo remote.