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DMGreenTech, BS Electrical Engineering
Category: TV
Satisfied Customers: 515
Experience:  4+ years installing AV, building EFI systems, analog/digital circuit design and assemby.
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How can I connect a coaxial cable wall outlet to a multi terminal

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How can I connect a coaxial cable wall outlet to a multi terminal cable box to a digital home theatre with CD/DVD player to an RF modulator to an old TV with only a coaxial cable inlet so that I can get picture and sound? A diagram would be helpful.
I think you're almost there.
I looked up your Motorola cable box, but couldn't find a reference to that model.

To best be able to help you, I'll need a little back and forth Q/A.

1) If you take the ASTAR home theater out of the mix and do the following:
Wall outlet -> cable box -> RF modulator -> TV - do you get picture and sound out of the TV?

Assuming you do in regard to #1, the only adjustment you need to make is to use two RCA cables (typically red/white) and go from the cable box to an AUX INPUT on your home theater system. This connection carries sound only, no video. You will have sound at both the TV and the home theater system, you simply turn the volume on the TV down.
Customer: replied 7 years ago.

Yes there is sound and picture.

However taking the home theatre out of the system also removes the need for the RF modulator. With that connection I have sound from the home theatre, but no picture; and there is sound and picture from the TV.

Installing the RCA cables as you suggested has no effect.

I have connected the DVD player from the home theatre to another TV and it plays sound and picture.

I think there is something wrong with the way I'm connecting the coaxial cables.

Just to make sure we're on the same page.
An RF modulator takes composite (usually a yellow RCA connection + red/white audio) and outputs it to RG6 (co-ax).

Here is a picture of a typical model:


What you're indicating is raising a flag to me: An RF modulator should not be required for a home theater connection - in fact, it would likely impede a home theater connection..

Can you detail exactly how your RF modulator is connected?

Note, I may be off base here - but it's hard to tell without a diagram or understanding literally what wires are where. If you decide you want someone else to help, just let me know.
Customer: replied 7 years ago.

This is an old TV with only one coaxial input. The RF modulator is required in this set up so to can be connected to the old TV.

Here's a drawing:graphic

OK.. That picture is exactly what I need. Thanks so much!

We're using the RF modulator incorrectly. It's not producing sound signals for your home theater unit.

Proper use of an RF modulator is to go from RCA style inputs to RG6 (cable type -coax) output. It's designed for use with devices that don't have RG6. It adapts RCA type inputs to RG6 TVs.

Using it as you have it configured, it's simply a pass through, which is why you're having trouble.

We'll see if we can find an alternative way to connect it.
Does your cable box have any RCA outputs on it? If you give me a model number, I can look it up
Customer: replied 7 years ago.

Motorola DCT2524/1631/AL

OK, I found your unit.. the back of it looks like this (please confirm):

Connect it this way:

CABLE BOX (use #7 output above) --coax cable----> RF modulator----->co ax--> TV

additionally: on the RF modulator, connect the yellow, red, and white connections to the CD/DVD player.

Let me know if this makes sense, if you need a diagram, I can do that for you a little later this evening.

Customer: replied 7 years ago.

That's the cable box alright. I have things hooked up as you suggested. I made a mistake in my diagram to you. There is no coaxial connection from the RF modulator to the DVD player.

So your

CABLE BOX (use #7 output above) --coax cable----> RF modulator----->co ax--> TV
additionally: on the RF modulator, connect the yellow, red, and white connections to the CD/DVD player.

It probably works the way it's supposed to, but it's not the way I thought it should. Thanks a lot for your help.


Bill, you're welcome... We're compensated for our time only if you accept our answers. Please let me know if there is something else I could do for you - or if for some reason you didn't find the answer acceptable.
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