From what my local retailer told me, it looks like I'm getting a 222 or 222k to control 2 out of my 3 SD TVs. How does the Duo work? I understand that it connects to one TV (let's say the living room) as normal. The second TV (let's say the office) is controlled with the Duo, but how? Is there some other small box that connects to the 2nd TV? Can someone explain the set up for me please? I'm curious.