Cat5 Joint

[wobblycogs]

I've got a slightly unusual telephone wiring problem and I'm wondering if anyone has a good solution.

Our phone line comes in on the ground floor in the hall but I need the ADSL router (the only thing on the line) in the office which is two floors up. Since there was no simple direct route between the two points I ran a piece of Cat5 from the master socket up to a slave in the office. Compared to the shorter Cat3 that I was using I got an extra 2Mb/s download speed so I was pleased with the result. The problem I now have though is that need to terminate the cable in a different place in the office - I'm building a server cupboard so it makes sense for the phone socket to be in there.

Pulling the cable back out of the office and running it to the cupboard is not an option, I'd have to take half the office to pieces to move it. Running a new cable all the way to the ground floor and across the house might be possible but it would be a huge job so that's out too.

The solution I'm planning is to cut the existing Cat5 cable outside the office and join a new run of cable to it. What I want to know though is the best way of joining the cable without harming the data rate too much. If possible I'd like to make it a Y joint and keep the old phone socket working but I don't care if that socket goes dead. My plan is to cut, pair back and solder each wire maintaining as much twist as possible. I'd rather a punch down extender but, unsurprisingly, I can't find anything like that. I wonder if I'd get away with a slave / master socket and punching down three wires into each point?

Annoyingly, the joint will have to be under the floor but I don't suppose the inspection requirements of mains wiring apply to telephone cable.

 

[Racers]

Hi, Mr Cogs

You could use a punch down extender and not cut the existing cable just strip the outer and puch down the wire with out cutting it. then add your new line.
That would make it only two wires in each terminal.


http://www.ebay.co.uk/itm/BT78A-Telepho ... 416144f08c


Pete

 

[wobblycogs]

Give that man a star, that's exactly what I've been looking for.

 

[Eric The Viking]

Don't be tempted to make a "Y" connection of any significant length: it will mess up the cable impedance and cause reflections that will drop your data rate dramatically. A punch-down extension ought to be fine, with one caveat: if you can find or make a screened box to put it in, that will help.

It's all low-impedance twisted pairs. You're right that keeping the twist as much as possible is good, but keeping the impedance as constant as possible is important too.

I can't remember which: if your ADSL router is high-Z, then the cable should have termination at the furthest end, irrespective of where the router is connected. I fear it's 100 Ohm* though, in which case it should be on the end of the wire, and you shouldn' extend beyond it because of reflections.

Not the answer you were looking for I guess. Try the "T" arrangement it and see how the router does. If the data rate is awful, disconnect the spur and try it with a simple "straight-line" path to the router. You never know you might get away with the "T", as so much depends on the cable lengths etc.

It's quite iffy technology really, given what it's used for. We've got 'cable' (broadband co-ax) coming into the house, and every time I see a very competitive offer from an ADSL provider, I'm tempted, until I remember it's ADSL.

E.

 

[wobblycogs]

Thanks Eric, that confirms what I was reading last night. I think I'm going to go with a straight through connection, as I won't have a phone connected it seems silly to risk a drop in data rate for a socket that won't be used.

One thing I read last night was that the ringer wire often causes interference because it's unbalanced. BT sell an iPlate that apparently reduces interference as it's only few quid so I'm tempted to try one out. I think I'll probably disconnect the ringer wire on the extension line anyway as I don't need it.

As for ADSL I couldn't agree more about it being iffy. It's amazing what they have managed to do with the installed infrastructure but it's time to move on and install a real data network. I had cable a few years ago and over all I prefer ADSL. I also need a fixed IP which, last time I looked, wasn't an option on any of the cable deals.

 

[Eric The Viking]

The ringer ("anti-tinging") wire starts at the 1st box. It's not used in ADSL at all. I didn't think it was connected to the incoming pair unless you had a standard British 'phone on the line (US-style 'phones only have two connections). If in doubt leave it off - it's easily reconnected if it's ever needed.

My IP address changes roughly annually, slightly more frequently if they're changing equipment upstream. If you have a commercial contract with Virgin (for SoHo and small business generally, they'll now do static IP for a fee. It's not enormous, but wasn't worth it for us, as I'm the only person in the house doing VPN, etc. I keep a record of when it's changed:

9/08,
2/09,
early/10 (don't have an exact record),
9/10,
4/11,
3/12,
4/12 (after speed upgrade). Speeds remain fictional though, and very asymetric.

E.

 

[AndyT]

We've been with Be for a few years now (http://www.bethere.co.uk

They don't do fibre yet but are unusual for offering fixed IP addresses (on the Pro service) and a genuinely unlimited usage tariff. Also line bonding. They actually encourage you to use your connection as much as you can!

 

[wobblycogs]

I'm already with Be (Unlimited Pro) and for the most part a very happy customer. They certainly aren't the cheapest around but they deliver what they say they will so I can't complain. I got the "switch over to IPv6" email the other day can't say I'm really looking forward to that - can't afford the down time if something goes wrong.

If there fibre service is as good as their ADSL they'll have a customer for life but I suspect it will be a long while before they wire up Gloucester. You might have some luck in Bristol though.

 

[JakeS]

My IP address changes roughly annually, slightly more frequently if they're changing equipment upstream. If you have a commercial contract with Virgin (for SoHo and small business generally, they'll now do static IP for a fee. It's not enormous, but wasn't worth it for us, as I'm the only person in the house doing VPN, etc. I keep a record of when it's changed:

I think ours (on Virgin cable) changes more or less at the same kind of rate... but for what it's worth, I've sidestepped it by using a Dyn dynamic DNS address. I use the free service just so I can access SVN and SSH from outside the house, so I don't need a flashy domain name, but they also do a paid service where they redirect a domain name to your changing dynamic IP address.