As posted by owlyn
above, they were the ones that provided a lot of the inside information on the side of things for Caller ID on the computer not working (btw, did not know that Caller ID on the TV was in the same mix, so that's good to know). I know there is thread on here where they talk about this in more detail. I did a quick search for it, but did not find it yet. If I do, I'll update this thread to include a link to it.
In regards to the TV side of things, let me tell you how things should be setup for it to work. Again, this assumes that all is well on Comcast's side of things, which, as owlyn
pointed out, won't always be the case. By the way, you don't need a phone jack for it to work. The signal for Caller ID comes down the same line as everything else; the coax line.
The settings that need to be set on the cable box are as follows
Press the "Menu" button on your cable tv remote. That should bring up a screen with all kinds of options. One of them should be "Interactive TV".
Select that one, and you should see a screen with the following options
• Caller ID
• Snooze Duration
• Location
I think by default, Called ID should have a value of "ON", Snooze Duration should be set to 1 hour, and location should be set to "Bottom of Screen". Feel free to modify the last two as you see fit for your needs.
If Caller ID is currently ON, you can try changing it to off, exit out of the menu to save the change, and then go back in and turn it back on.
You can also try to unplug your cable tv box (leave it unplugged for 3 minutes), and then plug it back in and see what happens.
If it still does not work, there is not much else you can do except wait and see if it starts on its own.
--Brian