The boxes are cute until you realize that there is no serial port and that there is no signal when going through the guided set up. I have mine working (right now at least) and here are the basic steps:
1) Connected everything the way I thought it should be then got to the screen that said I had a signal. Nothing worked from there and I became very unhappy. So decided to continue with the setup even though I got no video on my screen.
1a) REMEMBER THE IR TRANSMITTERS! There is no serial port. Make sure that your IR lights are on the far right of the DCT-700 when looking at it from the front (the sensor is about 3/4 of an inch from the end of the right side of the DCT-700)
2) Started to become resigned to the fact that I could not use this box for Tivo but I would not go down with out fiddling with it as much as possible. I just have the Tivo box, the DCT-700 and my TV so I split the signal from the coaxial cable so it would split into the Tivo box and the DCT-700. Then I took the RCA cables and connected it from DCT-700 out put to Tivo Input. Then I took another ste of RCA cables and connected Tivo output to TV AUX input. Then I took a coaxial cable and connected it from DCT-700 to TV input. My theory was that I could still use Tivo for the non digital channels and see (but not Tivo) the digital channels.
3) I think this worked but before I really fiddled around with it, this set up also enabled me to play with the Tivo settings to see if I could correct the problem. The key was then to go into setup on the Tivo menu and switch the signal Tivo uses (messages and setings - settings - video) until you get a signal. It worked partially and I was overjoyed.
4) I say partially because I could get most of the channels in the 30-40 region, one from 40-50 and all channels from 52-60. Then I started playing around with the wires and tried to reduce the tangled mess there was behind the equipment. In the end I figured that the splitter split the signal and slightly weakened it (I dont actually know if this is true) so not all channels came in. I finally removed the splitter and just had the cable from the wall go directly into the DCT-700.
5) Rejoice.

While some of my steps might be useless...it all worked. 2 Days later I did get a Tivo message saying that I need to set up video output because I skipped this step earlier. The message also warned me that I would not be able to use the Tivo recording features with out doing this but I deleted the message and I have full Tivo capability. If I keep getting this message or something else happens I'll try to keep all informed because I think that I am one of the first few with this box in the nation (Philly has it and my cable company in Atlanta told me 2 days ago that they only received the box this week) and this might cause a big and sad problem for many.
Chris