Etherley and telephone in same cat 6 patch cable.

[Siclark]

Hi
We just had new carpets laid and I had a cat 6 patch cable run under it to the desk which I have fitted sockets to myself.
I am now told we need a wired phone on the desk too. Short of pulling the carpet up again can I run telephone down any of the spare cores? The wall plate that the cat6 socket is on has telephone cable wired into it too so I could patch that into the cat 6 socket behind the wall plate and then maybe need an adaptor or just split the cable at the other end?
Is this possible or sensible?
Cheers

 

[sparkymarka]

You can get a cat 5/6 splitter BUT it may reduce your network speed , cost around £10 for the pair worth a go ...

 

[drgl]

If the network is running at Gigabit speeds it WILL mean a speed drop, if you are happy with 10/100 then there will be no speed drop. Also, you say wired telephone, is it the type that plugs into a BT socket or an office PBX system?

 

[Siclark]

The telephone would be a standard bt socket.
I thought even for gigabit there were unused cores for poe use, or does that mean any cat 5e/6 cable I use for poe is limited to 100?
This patch cable will be routing the main pc traffic between pc and nas and so not keen to lose the gigabit. Looks like I might be pulling the carpet up again as wife wants full desk phone there rather than a cordless one.

 

[drgl]

With Gigabit there are no unused pairs. You either drop to 10/100 (which is usually more than enough, what are you running?) or pull another cable in...

 

[Siclark]

I have cat6 cables everywhere to a gigabit switch and use a synology nas to store photos on which means heavy network traffic when on I work them.
So yes looks like new cable. of Out interest I have some new WiFi access points which have poe injectors to power them over cat6. They are capable of 300mbips but if i use them as poe does that mean they are capped at 100? Obviously more than done for Internet and mobile use but maybe not mefia streaming from the nas to TVs

 

[drgl]

No, POE does not affect speeds. The voltage is present with data, much like ADSL & phone line voltage. To patch a phone liver over the same cable you need a spare pair hence 10/100 only.

 

[Siclark]

OK. Cheers

 

[Mr Gear]

Hi
The wall plate that the cat6 socket is on has telephone cable wired into it too so I could patch that into the cat 6 socket behind the wall plate and then maybe need an adaptor or just split the cable at the other end?

So the telephone cable AND the Cat6 cable currently run into the same wall plate?
Is it 'live'? If not where does the other end of that cable go?
If it is (or can be made) 'live', don't you just need a modular face plate with 1 x Cat6 outlet and 1 x telephone outlet?
Or am I missing something...?

 

[Siclark]

The face plate is a grid one with yes, 3 x cat 6 and 1 x telephone point all run back to the main hub where the master socket is and I will wire the telephone cable into that. Yes, the idea was to plug the phone into there, but now it means the cable running across the floor which my wife doesnt like. So will be lifting the carpet I think.

 

[SimonH2]

To clarify on the PoE aspect ...
For 10/100 ethernet there are two spare pairs, and these can be used for dedicated power lines - called "Alternative B". This won't work for 1G because 1G uses all four pairs.

So a form of phantom power is used, where power is supplied as common mode voltage down the same wires as data. It uses centre tapped transformers, with power attached to the centre tap. The DC current through the two halves of the windings cancel out leaving the transformer free to handle the data. This is "Alternative A".

A couple of links that might explain it a bit better :
http://www.eetimes.com/document.asp?doc_id=1273086
http://www.maximintegrated.com/en/app-notes/index.mvp/id/4091

Incidentally, exactly the same is done to power microphones in the audio world. "Phantom power" applies +48V to both the signal wires, using the ground for the -ve return. At the mic end, a centre tapped transformer can be used to pick out the common mode supply - though there are also transformerless ways to do it.