can I use 2 wires of cat 5 to carry power to phone?

[wired-up]

I am putting in a base station/answering machine for my wireless phones in the garage entry on the wall. I ran cat 5 to the wall, but didn't think about the power supply. I don't want to run a cord from a wall wart up the wall to the phone mounted on the wall.
I could plug in the wall wart in the outlet below the phone location and fish the wire in the wall to the phone outlet, but then I'm still stuck with the wall wart in the wall in the entry hall.
Would it be possible to put the wall wart in the automation closet where the phone distribution is and use 2 of the wires in the cat 5 running to the phone to carry the power (9 volt, 500 mAmp, I think) without it interfering with the phone signal in the cat 5?
Whoever said 'Never enough wire" ... Amen
David

 

[electron]

I am assuming this is DC? But it shouldn't be a problem, I power my cameras that way.

 

[hult]

I am putting in a base station/answering machine for my wireless phones in the garage entry on the wall. I ran cat 5 to the wall, but didn't think about the power supply. I don't want to run a cord from a wall wart up the wall to the phone mounted on the wall.
I could plug in the wall wart in the outlet below the phone location and fish the wire in the wall to the phone outlet, but then I'm still stuck with the wall wart in the wall in the entry hall.
Would it be possible to put the wall wart in the automation closet where the phone distribution is and use 2 of the wires in the cat 5 running to the phone to carry the power (9 volt, 500 mAmp, I think) without it interfering with the phone signal in the cat 5?
Whoever said 'Never enough wire" ... Amen
David

If I were doing this, I would power the phone from a sealed lead 13.8vdc battery (nominal "12 volt") in the automation room through a 12volt, 1 amp regulator near the battery and a 9vdc regulator at the phone.

1) The battery provides power to the phone if the power goes off (and experience has shown that cell phone networks quickly go down during emergencies)

2) *VERY IMPORTANT* : The 12vdc regulator provides current limiting in case the wires are shorted. A sealed lead battery will quickly melt the insulation -- and worse -- of CAT5. If you aren't willing to put in some sort of power limiting (a fuse would be another alternative) don't use remote batteries at all.

3) The 9vdc regulator provides the voltage needed at the phone. Depending on how far the automation closet is from the phone, you might get by with a single 9vdc rgulator at the battery in the automation closet. Double up on the wires -- eg, a pair for the V+ and a pair for ground.

Preferably each regulator should have one or more capacitors on the input and output. This will require some soldering, but is easily accomplished. Google LM78xx or LM340 for lots of info on regulator ICs of the sort that are widely available including at Radio Shack.

There are at least two standard wiring configurations for Power over Ethernet (POE) (Google) and numerous sources of prebuilt and kit-based power supplies., eg
http://www.eidusa.com/Electronics_Kits_PoE_injector.htm

Note that one standard POE configuration transmits the DC power on the same wires as the (AC) data. I wouldn't do that for a phone ...

HTH ... Marc