Networks Power from RJ45

Does anyone know if I can tap power from an RJ45 cable without causing intereference or connectivity problems?

EDIT: with a 4 port Linksys deal. Didn't think so, unless someone has some new info, I have my answer (virtually none)

 

Yeah, the signal over a cat5 is very low, only for communication purposes. There is no power provided.

 

http://www.hyperlinktech.com/web/poe.php
have seen similar stuff for sale in the uk but cant remember
and they use it at school to power all the wireless access points
just a little box at either end of the cat5 cable, one end gives power out, the other power in and both have a rj45 port

 

Mods plz move this thread over to Networking....(kinda OT here)

 

Its entirely possible. PoE is done and since the cables are twisted pairs as long as you don't add too much voltage then it should be ok. Obviously only 4 of the wires in an RJ45 cable are used for networking so you could run 2 different voltages over it.

Look for any ethernet wiring diagram to show you which 4 are unused

EDIT: Its the blue and brown wires in a standard connection that are unused btw

 

Run some higher volts across the wrong wires and I think you stand to fry some stuff.

 

Ah yes, I thought you were referring just to the used wires. Of course you could send power through the unused wires...but like someone said, be careful how much or you risk damaging the wire or corrupting the signal.

 

Are you trying to strip power from the NIC or are you planning on adding power to the cable after it is sent out from the card? I have added low voltage to the cable, but you must strip off the power before it enters the NIC/router/hub etc. or you could damage the hardware. Also low voltage analog signal or power seems to work fine for just about any run of distance but if you try and add any digital signal to the wire it tends to overpower the original network packets.

 

hmm phire, we thinking of lit up ethernet cables, kinda likke the LED USB cables?

 

I've done a lot of work with IP Telephones, and they are powered from Switches which provide 48V .4A over the brown pair.

These *can* be connected to any ethernet device in theory, as those connectors shouldn't be internally wired. I've certainly never had a problem accidentally plugging one into a NIC.

As has already been stated though, the question is; are you wanting to run power over the cables alongside the Ethernet or do you want to *take* power from the existing signal?