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 it's 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.