This won't do what he wants. He wants to use a TiVo remote to control other things. If this works, it will allow his TiVo remote to control his TiVo by RF.

It's been several years since anybody mentioned this device. Since it hasn't caught on as the answer for anything, it's probably not.

IIRC, the way it works is that one of the normal batteries in each remote is replaced by a battery-sized RF transmitter that has room for a smaller battery inside of it. For instance, a AA-sized transmitter with an AA battery inside it.

I wonder what they do for the remotes that use AAA batteries!

It's a surprise to me that Ir commands can be sensed by looking at current draw on the batteries. One little filter capacitor in a remote would kill that capability.