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Coax CATV A/B switch question (1 Viewer)

RobertCharlotte

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Coax CATV A/B switches, you know, the kind you use to switch one TV (output) between two CATV sources (input)?

This weekend, I learned that they cannot be used to switch one input between two outputs. Why not? How could it possibly know which direction the signal is flowing, and why would it care?
 

Ted Lee

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because then it wouldn't be a switcher...it'd be a splitter. :)
i don't know internally how it's wired though.
 

Allan Jayne

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If it is a plain [pushbutton mechanical switcher with no battery or plug in power unit, it should have worked, allowed one source (such as an antenna lead in coax) to feed two devices (such as two TV sets) one at a time.
If it uses electronic switching, which most remote controllable ones have, it is for one way usage only.
Video hints:
http://members.aol.com/ajaynejr/video.htm
 

RobertCharlotte

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Very plain, similar to the Radio Shack model 15-1232. No push buttons, but a slide switch instead.
I guess my questions remain: why would it matter, and how does it know?
For the record, I thought it would work just like a splitter, too. In fact, I knew that what I needed was a splitter, but I had this lying around and didn't have any spare splitters, so I figured it would work. Wrong-o. :)
 

Bob McElfresh

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why would it matter
Think of it this way:

The switch takes 2 inputs and sends one/only one to a output.

BUT IT NEVER CONNECTS THE TWO INPUTS TOGETHER!

Lets say input A is your CATV feed. Input B is your VCR.

If the switch let A and B connect, whenever you played a tape, you would INJECT your VCR signal into the CATV system.

Could be embarassing when your neighbors notice that you are playing those tapes from the top of your bedroom closet. You know the ones I'm talking about.:b

So thats why. Input A/B must never "see" each other.

Hope this helps.
 

RobertCharlotte

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Sorry, I didn't explain my question clearly. Why would it matter which direction the data was flowing through the switch, even one leg at a time? If I have the switch on the "A" side, why would it care whether the data was coming in the "A" terminal and going out the "TV" terminal or coming in the "TV" terminal and going out the "A" terminal? It's the direction-sensitivity that I don't understand.
 

Allan Jayne

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Try it again, also try it using the B side. I'm sure that a mechanical switch does not care which direction the data was going. Maybe you had a bad connection or a bad cable. Maybe the switching didn't quite make contact the first time because it is of poor quality.
 

RobertCharlotte

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Feb 21, 2002
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One side actually did work, but when I switched it to the other side, there was no signal there. It was weird. At any rate, there's not really any point trying again, Allan. I went on out and bought a splitter to use, since that's what I needed anyway.

Like Tom and Ray always say, it's the stingy man who pays the most.
 

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