What digital box do I need if i get Comcast Cable for free?

I need help with my comcast cable box?

• I have an HD motorola DCH3416 box. I also have HD service from comcast. We recently purchased a new sony HD tv. We completely forget how to hook the box up to the tv. When we got the box we were given the typical white cable cord, and a set of 5 wires, which have 2 red, one blue, one black, and one white wire. i figure these are the wires that plug into the Pr and Pb and audio holes. I honestly dont know what Pr or Pb is. Do i need these 5 wires to get the HD picture? If so, which wires go in which holes? the holes are as follows: Pb, Pr, V, L, R, and Y. I tried plugging wires into what i believe the right place should be, but i dont really notice much difference between the picture of HD channels and the normal channels. Basically, the white cable wire gives me the channels themselves, but do i need the component cables to get the HD? Thanks for help!

• Answer:

  So first ~V, the yellow jack, is composite video which is SD only. Don't use that input (AV/Video)except for 3 RCA connections to games and SD devices. 5 RCA connections aka component video can be HD and are Pb (blue), Pr(red), Y(~green/black), and red(left) and white(right) audio. The red video (Pr) may be a heavier cable than red(right) audio. Use the component video set of jacks only and switch the TV to that input. Don't confuse composite (yellow jack) with component video (red,blue,~green). I'm not going to look up your box specs but you should look to see if it has a HDMI output. HDMI combines everything on one cable and the signal is digital, not analog. But buy HDMI cables on the internet or get ripped off by stores who use them to boost profit by charging $50 for HDMI cables. I should mention that Comcast does not scramble all channels so you can split the RF (coax) to your TV antenna input and scan for clear QAM channels, many of which are HD. Also note that many channels on comcast are still SD (standard definition). Normally you do not use the RF (white cable?) when you are using a cable box. You should be using the cable box to navigate channels 1 to 999 in the Comcast menu. If the cable box has a RF output, it's probably intended for old TVs and therefore not HD.