I just converted my digital box today with a splitter. My control box did not have coaxial input/output (on my coach, the coaxial cable comes directly from the antenna to the TV, not through the control box and the DVD player and satellite dish receiver go through the control box and input/output are wired with red, yellow, and white wires). Using the coax cable from the antenna, I tried to set it up with two splitters wiring through and around the digital converter. Short story, it did not work. Then I added an A/B switch. I put the A side coming out of the digital converter and the B side to direct cable and voila, it works great. I now can use the A switch for digital TV and B for regular TV (at least for the next few months) and cable. Good luck with your project.
2008 SuperNova (6331)
2011 Jeep Wrangler (Toad)
Now: 2011 Winnebago Journey Express
2011 Silverado 4x4 Texas Edition Extended Cab (Toad)