Linking BT master terminal to distant router

[jim_in_sussex]

About to instal broadband. The BT terminal is at the top of the house in an attic, whilst the wireless router will be on the ground floor. It is planned to supplement the wireless channel with direct CAt5 cabling to some rooms.

There will be a master filter just after the BT terminal & the existing telephones will branch out from there.

The plan is run the unfiltered (ADSL) telephone (AB) line downstairs to the router using CAT5 cable.

Q1 Assuming that is OK, which are the correct colours to use in the CAT5 cable?

Q2 Is it correct that each RJ45 socketed ethernet channel on the router only require 3 wires ? If so, can the unused 6 wires in the CAT5 cable be used to feed a RJ45 socket to the router? - if so, which cable colours carry the signals?

ie like this:

master BT master ----ADSL filter --unfiltered signal>>>>>-[CAT5 cable]-------------------RJ11 -------router I socket I I------>filtered telephone lines>>>>>>[existing telephone cabling]

RJ45 >------[CAT5 cable}---------------> RJ45

--[patch lead]----> router

wall socket wall socket

As this apparently leaves spare wires, would it be possible to feed the filtered telephone line down this same piece of CAT5?

also any comments on practicality most welcome

TIA

[Andy Hall]

The first pair used is normally the blue.

Peter Parry's site has more details

Ethernet requires 4 wires, so this would leave two pairs unused.

You might get away with what you are suggesting, but it is bad practice to mix services in one cable. It might not cause a problem at 10Mbits, but if the link is set or negotiates to 100Mbit, then there is a fair chance that the ethernet will run unreliably.

It is best to use one cable for each service and to keep them separate. Run more cables if needed - the cable is very cheap.

[Set Square]

Rather than use a plug-in filter, I would use a Clarity modified filtered faceplate in the master socket, as described at Clarity Modified Master Faceplate You can then hardwire a digital extension into the back of that, along with your normal telephone extension wiring. The digital extension only requires one pair - so you could certainly use another one and a half pairs in the same CAT5 cable for phone extensions. It's not a good idea to mix ethernet with anything in the same cable though, so I would use additional CAT5 cables for that. This will presumably need to be a star setup, centred on your router, anyway.

[The above Clarity link *should* work - their website seems to be down at the moment]

[Set Square]

Well, it *looked* like a link in the previous message before I submitted it! It should have been

[David Hansen]

On Tue, 29 Nov 2005 22:20:28 -0000 someone who may be "Set Square" wrote this:-

also rightly says in places that if you don't understand the diagram then consider getting someone else to do it.

[Paul ( Skiing8 )]

saw this a while ago and thought it was a good idea. I had a normal BT supplied ADSL faceplate and I got thinking about if it was possible to modify it. Turned out really easy, I popped the blastic back off then soldered a PCB terminal block thing in place. The holes and connections were already there so it was an easy job. Then I had to make a cutout in the plastic.

[jim_in_sussex]

TFT

....

Understood - but it's going into my parents home & is only being installed for convenience when visiting, not posterity. However given what you say, What is the best choice of cable?

requirements are:

A) to take the unfiltered AB signal downstairs (about 25m) (all speech telephone cables being filtered off at the entry point) - essential

B) Take a new speech telephone cable to near the router from the filter point. - useful only

C). Bring back part way (to 1st floor) a CAT5 cable to carry ethernet to/from the router. - high up in the wants.

For A) is CAT5 really needed? Won't ordinary telephone cable do? After all the signal travels unfiltered 3/4mile or more from the exchange on normal BT cable.

For B) ordinary telephone cable will do, but if that is OK for A) & I try to use the same (6 way) cable as for A then is there a risk of cross-talk?

For C) clearly a dedicated CAT5 is what you're recommending - will do

There's something I don't understand here - why is CAT5 the standard cable when apparently only half the cable is used (4 wires out of 8)?

Also what are the standard pairings on CAT5 for sthe standard PC router ethernet signals?

++++

Other posters have mentioned the Clarity master filter which is the one I will be installing on this job. One is already in use in my own home & it works just fine - my home system cabling splits into separate speech and ADSL networks at the front door. Highly recommended.

[David Hansen]

On 30 Nov 2005 02:51:01 -0800 someone who may be "jim_in_sussex" wrote this:-

A tall house:-)

I suspect not much chance. If you use Category 5 cable it is more twisted and the chances are, I suspect, even less.

All eight wires have been used in some networking implementations.

ISTR that the Clarity site gives all this. If it doesn't there are search engines. Many data sockets come with colour coded identifiers for which cable goes where. The main thing is that wiring is straight through, with pin 1 being connected to pin 1 and so on.

Then it probably came with a little leaflet that explains the wiring colours in some detail.

[Andy Hall]

No it isn't.

Yes, although if you're having to buy a reel, then it may be cheaper to just get one cable type.

It's unpredictable. That's really the issue. You could put it in and it might work and then not and be intermittent. It's much easier to thread two or more cables while you're at it than to have to go back.

Other pairs are used for other purposes but not at the same time down one cable.

There are two standards for the cable wiring

the pin numbers on ethernet remain the same.

Another thought if you don't want the cable hassle is to go for wireless. There are some good bundle deals on 802.11g and even Pre-N products.

[Set Square]

Ordinary phone cable is fine. If you use 3-pair cable, you can carry voice and digital in a single cable.

No it will be fine. As far as cable colours go, use the blue pair for voice (2+5) one of the orange wires for ringer (3) and the green pair for ADSL.

I'm not sure how many computers will have a wired connection to the router - but you need a separate CAT5 cable for each one - unless you're putting an additional hub somewhere. It doesn't daisy-chain like thin co-ax ethernet!

See

It's best to use RJ45 sockets with solid CAT5 between them, and short flexible patch leads each end.

[Chip]

On 30 Nov 2005 02:51:01 -0800,it is alleged that "jim_in_sussex" spake thusly in uk.d-i-y:

[snippage]

3 separate cables would be best.

Ordinary telephone cable would be fine for both DSL and Voice signals yes. It has the advantage of being slightly smaller than cat5.

If you use all 3 wires required (Including the bell shunt) then yes, crosstalk will likely become a problem (How much this would affect ADSL I am not sure). Running the voice line as just A+B (2+5) and using master sockets at the extension points would likely prevent any potential problem, at the expense of causing bell tinkle should you ever use a pulse dialling phone.

In 100baseTX or 10baseT ethernet -which are the most common- this is true, some variants of gigabit ethernet can operate across cat5 cable using all 4 pairs however. It's considered good practise to connect all 4 pairs, allowing future use with whatever standard is required.

Assuming the router uses EIA/TIA 568B (which is the most common)

white/orange = Transmit Data + orange/white = Transmit Data - white/green = Receive Data + blue/white = Spare white/blue = Spare green/white = Receive Data - white/brown = Spare brown/white = Spare

[tony sayer]

I

Interesting that. The Brown pair are used sometimes for power over ethernet are they not?. Tried to put a temporary phone line down a brown pair this afternoon on a cat5 data cable, but it was shorted out by something in the netgear router connected on that line?...

[look]

As for length of telephone cable between master socket and router/modem. I am using a cheap 20m min ribbon phone extension cable (Woolies) from a socket whose wiring goes all round the house. No problems with broadband at 2Mbs.

Robert

[Chip]

On Wed, 30 Nov 2005 18:57:38 +0000,it is alleged that tony sayer spake thusly in uk.d-i-y:

Hadn't even considered power over ethernet, good catch.

Certainly possible, there seem to be many variations. On the computers here, one no-name network card shorts the brown and blue pairs, one is open on all spare lines. With 'power over ethernet' becoming more common, attempting to use these pairs for anything else is hazardous I guess. The eTec dsl modem/router thingy in the loft appears not to be shorting anything.

[The Natural Philosopher]

The signal has already dione a couple of miles ovcer very indifferent and not-all-that-twisted pairs - a few more meters makes very litle difference.

However I generally prefer to keep teh ADFSL kit over BT lines and do the rest via tehernet..if only because it makes things tidier.

CAT 5 cable is used for structured installatins BTW because irt is capable of taking most common signals - ethernet, phone, and serial and token ring data (thoiugh that is not used so much). In short its good enough for almost antyhing up to 100mbps.

The cost of halfway decent cat5 is pennies compared to te cost of ripping up floorboards and laying it, so why mess around.

AND as I discovered to my cost yesterday, its a sight tougher than telephone cable in terms of fracturing under stress. Grrr.