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Cabling query

JohnWoodhouse
Newbie
Posts: 3
Registered: 13-06-2011

Cabling query

I hope this hasn't been answered at length before....
My present set-up has a BT master socket in the cellar with a splitter in it. From there a standard 4-strand cable goes two floors up to my study and router.
I am due to be upgraded to FTTC next week and want to know whether:
I should have the modem installed by the master socket and feed a new CatV cable up to the study to connect the new router, (there is a convenient power socket in the cellar)
OR
leave the existing connection cable as it is and have both modem and router installed upstairs.
I rather suspect there would be nothing gained by going to the trouble to pre-install a new CatV cable (a length of some 22m), but I thought I would ask before the BT fitter comes? (Sections of ceiling would need to be removed in the cellar and I would rather do that myself than leave it to the BT man)
Thanks,
John
11 REPLIES
phil4
Grafter
Posts: 244
Registered: 13-12-2007

Re: Cabling query

My understanding is:

BT will want to fit the modem next to the master socket.
This can be negated in the following ways:
1) Turn the slave socket into a master socket, something they may do for you, if that's what you want.
2) Move the master socket - again can be requested, but there are restrictions as to where they will put it.
3) Use a "data extension kit", to locate the modem upto 30m away, this will normally just be tacked to skirting, no holes drilled.
4) Your method, also what I use, of having the modem next to the master socket, and using a CAT5e cable to get it to where it's needed (ie. my router).
HTH, only have first hand experience of 4.
AxeMurderer
Grafter
Posts: 164
Registered: 18-05-2011

Re: Cabling query

1. BT can, trivially, convert an existing extension into the new master* (and the old master into an extension). They did that for me, and it appears to be a standard, no-cost, option.
2. They can move the master socket but that might be chargeable
3. They can use a data extension cable as you describe. If they have such a cable. If they don't you can buy something equivalent and move the modem afterwards (it is just a longer version of the  ~1m cable that BT will supply to connect to the modem i.e. telephone-extension cable with RJ11 plugs on the end).
4. And of course you can use Cat5 up to 100m.
5. Any combination of the above
#1 for the win though

*there may be restrictions if you have chains of extension sockets snaking all over the house
JohnWoodhouse
Newbie
Posts: 3
Registered: 13-06-2011

Re: Cabling query

I may not have phrased my question quite as I wanted to.
The real question is whether it is better to
a.) have the modem at the master socket in the cellar, and a CatV cable for 22m up to the study to the new router
or
b.) use the existing cable (which is 4 x single conductors of 0.48mm, as used in burglar alarm systems) from the new master socket in the cellar up to the study and get the installer to put both modem and router there.
I suppose, in other words, is there going to be more loss from the existing cable upstream from the modem, or from CatV cable downstream from the modem?
John
itsme
Grafter
Posts: 5,924
Thanks: 1
Registered: 07-04-2007

Re: Cabling query

Quote from: AxeMurderer
1. BT can, trivially, convert an existing extension into the new master* (and the old master into an extension). They did that for me, and it appears to be a standard, no-cost, option.

If this is done properly than a 6 core cable is needed from the old master to the new master. As it standard to only use 4 core cable for extensions then I would say that this is not an option for the majority of houses.
AxeMurderer
Grafter
Posts: 164
Registered: 18-05-2011

Re: Cabling query

a) will be better, but will it make enough of a difference to be noticeable? I have about 5m of the same rubbish cable that you have before my new master socket, and I had another 3m of standard RJ11-terminated cable between that and the modem. I was still getting up to 39Mb/s.
I have now replaced the RJ11-terminated cable with a longer one I've made myself out of cat5. I did this so that I could route the cable more conveniently without expecting any speed improvement. I also plan to replace the rubbish cable with cat5 too* but this is precautionary - the cable runs outside the house and is not exterior grade even.
In your position I would let the BT guy put the new master socket upstairs where you need it and see what rate he gets. Unless it is way down I'd leave it. If it is down you could try asking him to move it back and/or put a better quality cable in after he has gone*.

* I don't think this is 'allowed' but I'm prepared to take the chance especially as it is MY cable that I'll be replacing.
AxeMurderer
Grafter
Posts: 164
Registered: 18-05-2011

Re: Cabling query

@itsme
BT have used just two of the four wires in my pre-existing cable.
jedi98
Grafter
Posts: 46
Registered: 04-08-2007

Re: Cabling query

IMO definitely put the modem as close to the master as possible then run a long CAT5 to the router. The extending a VDSL modem cable degrades the line. However, the cat5 from the modem is 10/100 ethernet and will run a minimum of 30M with no trouble, but more to the point most 10/100 ethernet will drive over 100M without errors. This is how I wired my colleague’s system.
Ethernet is designed to run at 100% until it stops working completely. VDSL is designed to degrade gracefully over distance.
AxeMurderer
Grafter
Posts: 164
Registered: 18-05-2011

Re: Cabling query

@JohnWoodhouse
I didn't read your b) properly. I think the one thing the BT engineer won't want to do is to convert your extension cable to a 'data extension cable'. I really think you want the master socket and modem close to each other, and in your case, upstairs. If you have the master socket in the cellar you need to make two connections to it, one for your phones, and one for your modem. But you have only got one wire at the moment and it hasn't got the right connectors on it. You could make a hideous frankencable from it but I don't think BT will want to.
JohnWoodhouse
Newbie
Posts: 3
Registered: 13-06-2011

Re: Cabling query


OK, thanks to all for the various comments and suggestions.
Much appreciated.
John
Community Veteran
Posts: 5,283
Thanks: 448
Fixes: 1
Registered: 21-03-2011

Re: Cabling query

If you do use the CAT5 cable make sure you use either the T568B or T568A wiring scheme for connecting the conductor wires in the CAT5 cable. There are specific "rules" for which colour of wire is connected to which pin of the plug/socket. A quick Google session will find those.  If you use the incorrect conductor pair sequence on the CAT5 you could increase the signal error.
Now Zen, but a +Net residue.
TonyC
Grafter
Posts: 43
Registered: 15-02-2008

Re: Cabling query

Quote from: itsme
If this is done properly than a 6 core cable is needed from the old master to the new master. As it standard to only use 4 core cable for extensions then I would say that this is not an option for the majority of houses.

When I had my Fibre installed, I had the master socket moved upstairs to the study, with the old socket as a secondary by the front door. (I didnt actually have an existing NTE5 socket)
I had already lifted the floorboards in the study for him, and the engineer actually replaced the extension cabling with new cable through the existing hole in the ceiling. Faultless, and the engineer was more than happy to do it.
I think as long as the route is there, they will pass cables through walls/ceilings etc. Just don't expect them to make a route.