I just got the idea to run cables through the walls to transmit data around the house. In particular, I was thinking of buying a few HDMI/RCA/Coax/Ethernet wall plates and installing them in a couple of different rooms so that we can, for example, plug in a blu-ray player in one room and have it output in another room. (Ideally, we'd be able to set up one room as the "hub" and use splitters to send the data to the other rooms, but one step at a time here)

Basically, the plate in one room should serve as an "input," while the plate in another room should serve as an "output." Of course the cables themselves don't care, but that would be the "rule" so to speak. In one room, you plug in something that makes a signal, but in the other room, you plug in something that uses that signal.

But with the device on the other end of the cable being in another room, it would be pretty easy to forget and accidentally hook up a blu-ray player to a PC, or a DVD player to a DVD player, or a TV to a TV.

So my question is, what happens in these cases:

  • HDMI out to HDMI out (eg blu-ray to blu-ray)
  • HDMI in to HDMI in (eg HDTV to HDTV)
  • RCA out to RCA out (eg DVD player to DVD player)
  • RCA in to RCA in (eg SDTV to SDTV)
  • Coax out to Coax out (eg VCR to VCR)
  • Coax in to Coax in (eg TV to TV)

Hopefully, in each of these cases, nothing bad happens (or nothing happens at all). But the older standards worry me a little bit. Would any of these situations result in damage to the devices, or are these standards "smart" enough to detect this kind of thing and react properly?

Sorry if this is more of an electronics question.

Thanks for any help.

  • 3
    HDMI is bidirectional and involves a handshake between devices (for e.g. HDCP). They are smart enough not to damage anything if you connect them incorrectly. But you will need to watch for cable length. While there is no official maximum length, anything longer than around 15-20 feet risks signal degredation. Being a high-bandwidth digital signal, it can deteriorate very quickly.
    – user4302
    Jun 10, 2016 at 22:05
  • 1
    Most people I know solve this by using what I'd call a "Media Server" that can handle BluRay, Audio, Internet, etc. Rather than stacking up multiple devices, you can move to 1 that can handle all these different tasks in one, upgradeable unit. The method of transmission is likely to change as TVs go to higher and higher resolution and screen refresh. +1 to Harper for suggesting conduit if you still want to do something like this, understanding your distance limits. Jun 13, 2016 at 12:32
  • Agree with @BrownRedHawk - go with a media server or HTPC (home theater PC) and then the only cabling you need throughout the house is ethernet. If you've got a PC and a Roku / Apple TV / Amazon TV, you could set one up right now using Plex without moving anything around
    – mmathis
    Jul 28, 2016 at 19:59

1 Answer 1


The problems you are trying to solve -- so is everybody else. There are a lot of consumer products on the market aiming to solve the "how do I put my TV here" problem. Their "universal solvent" seems to be ethernet or WiFi.

You're saying pre-run all the above wires to an appropriate central place - somewhere a wife would authorize a bunch of tech gear to be stacked up.

I wouldn't do that. I'd run the fattest conduit you can manage. That way you can pull any cable that may be required in the future - Cat7, Lightning, USB3, whatever.

Coax (I assume you mean RG6 cable TV coax) generally implies RF frequency. Two Coax devices can drive into each other without incident.

RCA (which is also coax) - I would not expect two outputs to damage each other since their output is line-level. (a line output against a phonograph needle output - different deal.) Anyway that makes me laugh - I haven't used RCA connectors in AV for over a decade, except obviously for line-level audio, and that doesn't like going a long distance.

Ethernet will be fine. Plugging nose-to-nose happens all the time when you use a regular cable when you should've used a crossover cable, or vice versa.

HDMI is negotiated. But HDMI is not going to work over any kind of distance, and you have a lot of gratuitous distance going to the concentration point and back out to the other room. Also several connectors.

  • Good idea about the conduit. Looks like they do make pass-through wall plates, but I'm not sure I like the possibility of cables falling back through or toy cars "mysteriously" ending up in the walls. Converting everything to ethernet doesn't sound like a bad idea either. Thanks for the help.
    – Devsman
    Jun 13, 2016 at 12:36
  • 1
    With conduit, I don't mean a 1-1/2" hole in your wall that kids can stuff macaroni and cheese into. I mean the conduit comes up to a common junction box, just like outlets use, and then you fit a cover plate similar to an outlet cover plate, but with a connector socket. Or if necessary, a cover with a grommeted hole in it. Jun 13, 2016 at 21:49

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