Help with Coax Wiring Configuration

[kpierce]

My question is around wiring. My media room is pre-wired for an overhead projector, surround sound, etc.

I have the 5 plates in the wall where the speakers go and I understand that part.

In the ceiling I have two pair of Coax cables in a junction box. I also have a small TV already running in the room. I told the cable guy to hook up the outlet in the wall. I pulled the plate from that outlet and it has two pair of Coax cables as well.

I have comcast and he told me they only utilize the single line now so only one of the coax cables it connected to the face plate.

My question is how does all this fit together?

I understand the cable singal comes into that wall plate, I would hook a HDTV Cable box to the 'hot' coax. Is the other coax to run the signal from the cable box to the projector? That would make sense, but I would like to verify. Basically is this wire just from the wall outlet to the ceiling?

If this is the case why are there two sets of Coax in the ceiling is one in case I have receiver right there at the ceiling? So it would be hot and carrying a video signal? I have not taken the time to crawl back in the attic to look.

Finally, How can I figure out in the ceiling which wire is carrying the video signal, and which is not? Just trial and error?

thanks
kendall

 

[BMXTRIX]

f'ing retards

They have no clue how to wire a projector and you are now screwed.

Yes, that's right.

Video comes in from the cable company all mixed together and a cable tuner, found in VCRs, TVs, cable boxes, etc. puts them all on separate channels and outputs the video.

The video from a VCR comes out on a single piece of video cable as a coposite signal.

Composite = 1 75ohm cable - lowest quality - traditionally used for years

A step up are digital cable boxes (non-HD) that include S-Video output

S-Video = 2 75ohm cables - mid quality - not often used, but better than composite, typically uses a round connector on the end with two 75ohm cables put together in a single case so it looks like just one cable.

Now you are talking about HD cable...

For this you need a HD cable box and the ONLY way to get HD from the box to your projector is by utilizing one of two different methods.

Component video: This uses 3 75ohm cables and is the most common way of connecting video devices. The 3 cables come out of the cable box and can be connected straight to the projector or can go into a A/V receiver which will allow for you to hook up HD cable & a DVD player using component video. Once again it requires THREE cables.

Digital connection: There are two standard digital connectors that carry HD video and those are DVI and HDMI. They are a single cable with multiple wires inside and carry the information in a digital format. Potentially, this can increase video quality over component cables - not always though. I have not seen DVI or HDMI cables that allow you to put the ends on yourself, so these cables can be a bit difficult to run through the wall after the wall is up. Retrofitting with these cables it tough.

TO ANY PROJECTOR:
The minimum cabling requirements, in my opinion, are as follows:

Run 4 pieces of video 75 ohm video cable to carry component (3 wires) and composite (1 wire)

Also, have power at the projector.

At this point I would always install a HDMI cable at the projector location as well. For HD discs coming out next year, HDMI or DVI is a must and HDMI is the newer way to go and is backwards compatible with DVI - so use HDMI.

Right now, with only 2 cables at your projector there is no way you can watch HDTV on it. Almost no projectors have TV tuners built in and none have HD television tuners built in.

I would take this up with whoever you paid to properly install the 'projector' as they are 100% clueless as to how this technology works. What are you gonna do, but a cable box on your ceiling and strap it to the projector?

I've gotta get my consultation business started - I'm tired of seeing people like you dish out their cash only to get screwed over by a clueless company who has no problem pulling the wires, but has no clue what wires to pull. I am quite sure you will find a fair number of other issues that haven't been discovered yet as well.

Good luck.