UPDATE 1/18/10: Followed MLD’s advice from Jan 6 — and it worked — the Tivo serial cable works better than the IR blaster. See my comment, below, dated today.
My long cable box to Tivo nightmare is over. I’m posting these instructions for those who may go through the same horrid mess. I didn’t find these anywhere.
Comcast in Berkeley — from who I have gotten truly terrible customer service throughout this — is switching to new, digital equipment; independent of but, to confuse things, simultaneous with, the larger digital changeover. I have talked with roughly two dozen people at Comcast (I’m not exaggerating) and gotten every possible story about whether I can, and if so how, still use my Tivo Series 2 and my analog TV with their new box. I have a perfectly good TV and a Tivo box with lifetime service; I had no intention of buying new ones, not just now. I find it annoying enough that I have to pay for cable, but the TV I watch is almost exclusively on cable channels.
Ta-da — here’s how you do it.
1. Get a Tivo IR Blaster. In theory, this came with your Tivo. It enables the Tivo remote control to control your cable box. If I did have one, I have no idea where it is now. I got one at Weaknees.com – they sell other Tivo accessories. I was told to be sure to get the kind where the sensors at the end turn at 90 degree angles, like this you see in this image from http://www.weaknees.com/tivo-cables.php
The purple end plugs into the back of the Tivo, into “channel change – IR”.
Use a flashlight to see the IR receiver behind the dark glass in front of your cable box. The two “boot” ends go over and under the box so that they both shine on the IR receiver, though another images from Tivo suggests you can get away with just one sensor:
2. Run the cables from wall to cable box to Tivo to TV.
3. Go into Tivo settings and have it run setup again. You have to tell it that you’re using a cable box (which I wasn’t before), and it has to figure out which one, which is what the setup process allows you to tell it to do. (There’s probably a more direct route than running setup all over again, but I didn’t think of that in time.)
4. Make sure the Tivo and the Cable Box both require the same TV channel (slider on the back of the Tivo picks 3 or 4) and set the TV to the correct channel.
5. Finally! You can control Tivo and the cable box simultaneously, using the Tivo remote control, and the Tivo can record from cable. Until I did all this, I could (1) set tivo and tv on ch 3 and see whatever channel the cable box was set to, but (2) could not record.
It has taken me approximately a month, two dozen calls, one visit to Comcast, and one visit from a Comcast service person. The latter finally was able to tell me what to do (thanks, Keisha!) but couldn’t get things set up because I didn’t have an IR blaster. And she didn’t tell me that I had to rerun Tivo setup once I got it — I was stumped at why I had all the pieces connected but they weren’t working together.
Update July 28: One more thing: it only records correctly if I leave the Tivo box ON. That’s a waste of energy, but I had trouble recording — it thought it had the right channel, everything looked right, the show listed was the one I asked to be recorded — but the content was wrong; it wasn’t changing channels. It seems that the only solution is to never turn the Tivo box off.