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Christmas is on its way, let the REIN fall
Monday 03 December 2007 16:30:56 by Andrew Ferguson

REIN stands for, Random Electrical Impulse Noise, and it is very often the reason for those seemingly random disconnects on your ADSL connection.

This is the second Christmas since rate adaptive products from LLU providers and BT Wholesale have been used by millions of people in the UK which means the number of people who may see yet more disconnects over the Christmas period is a lot higher than in the past.

What many people may not know is that while a phone line will happily run a 0.5Mbps connection in the face of almost any form of random noise, run the same line at the maximum it will support and the safety margin decreases to the point that something as simple as a set of Christmas lights blinking on and off may be enough to cause disconnects, or slower speeds than previously experienced.

The moral is that if your ADSL starts to run slow and your Christmas lights are on, try switching them off and restart the ADSL modem to see if things improve. If they do, consider moving the Christmas lights. Things to avoid are running Christmas lights close to the telephone wiring, or plugging power transformers into the same power strip as an ADSL modem. It may actually be your neighbours lights that are the problem, so some delicate discussions could be required. If they have ADSL themselves, they may welcome some help in figuring out what the problem is.

In cases where the disconnects are not resolved by switching things off or moving it, then ensuring the telephone wiring inside your property is not picking up more noise than it needs to is a good idea. The simplest and fastest solution is to disconnect the ring wire on all your extensions and master socket. If you don't mind waiting for the postman to deliver it, fitting a dedicated ADSL faceplate to the master socket is a good project to keep you out of the shops. One final word, if you are using a flat ribbon type cable for connecting your ADSL modem, we would advise changing this for a cable that has twisted pairs. Twisted pair cabling is what BT use for the cable to your home and for BT installed extensions (unless your wiring is very old) and it helps to make the ADSL signal more immune to noise.

Comments

Posted by adslmax over 9 years ago
One final word, if you are using a flat ribbon type cable for connecting your ADSL modem, we would advise changing this for a cable that has twisted pairs. Twisted pair cabling is what BT use for the cable to your home and for BT installed extensions (unless your wiring is very old) and it helps to make the ADSL signal more immune to noise.


What is twisted pairs cable look like ?
Posted by adriandaz over 9 years ago
Flat cable:
http://www.solwise.co.uk/images/cable-flat4.jpg

Twisted pair cable:
http://www.oftc.usyd.edu.au/edweb/revolution/technology/images/twisted_pair.jpg
Posted by herdwick over 9 years ago
"What is twisted pairs cable look like ?"

generally round in cross section, rather than flat.
Posted by andrew (Favicon staff member) over 9 years ago
I'll try and get a reasonable picture and add it to the FAQ
Posted by csimon over 9 years ago
Are cables that are sold as "fast modem cables", or something like that, generally twisted pairs? If not, I don't think I've ever seen any ready-made cables in shops that specifically say twisted pair.
Posted by 3t4nM4n over 9 years ago
so if my ptsn line is supplied by the pole and my neighbours have external xmas lights then i should expect some interference ?
Posted by 3t4nM4n over 9 years ago
also clarity.it sell some "performance modem cable" looks fatter than cat5 cable :)
Posted by 3t4nM4n over 9 years ago
http://www.clarity.it/xcart/product.php?productid=16185&cat=253&page=1
Posted by herdwick over 9 years ago
yes there are cables in DIY stores that are twisted pair, usually round and you can often see the twists under the outer sheath (some are transparent which makes it even easier).

Focus DIY had some with a BT plug one end and RJ11 the other, ideal for plugging a router to a BT socket, others were RJ11-RJ11.
Posted by jcym over 9 years ago
3t4nM4n, so if my ptsn line is supplied by the pole and my neighbours have external xmas lights then i should expect some interference ?

Depends, how stable and fast is your ADSL now, especially in the evening when interference is usually worst for a number of reasons? I.e. it is something to be aware of if you start to notice dropouts or slowdowns that you previously didn't get but it doesn't necessarily mean that you will get problems.
Posted by andrew (Favicon staff member) over 9 years ago
You may get some interference, not all Christmas lights are a problem. One problem is that the lights usually come on as the sun sets which is already increasing the amount of AM range noise, hence suggestion to try turning them off to see if it helps.

Posted by jelv over 9 years ago
"The moral is that if your ADSL starts to run slow and your Christmas lights are on, try switching them off and restart the ADSL modem to see if things improve."

The problem for people on MAX is that if the interference has caused their IP Profile to drop they will not see an immediate improvement - it could take up to three days. I think you should have explained this aspect.
Posted by csimon over 9 years ago
"there are cables...that are twisted pair, usually round"

Only last weekend I bought a "fast modem" cable from B&Q. It's not transparent so I can't see what's underneath. It's not round like a CAT5 cable, but then again it's not flat either like the original one with the router, it's more like an oval with two definite "corners". I think it's given me around 1dB more SNR margin! I also have a 10m hq cable, transparent, much like the Clarity one linked above, but it actually loses about 1dB compared with the original cable probably because it's so long.
Posted by csimon over 9 years ago
Stupid questions possibly, but I have wondered about this and always been afraid to ask!

Does it make any difference if the modem cable is unwound or whether it's coiled up to take up the slack?

Would wrapping the cable in tin foil make any difference, as though it's adding an extra layer of shielding?
Posted by Balb0wa over 9 years ago
whats the shortest rj11-rj11 available?
Posted by csimon over 9 years ago
Oh yes, that's another one I wanted to ask, thanks!
Posted by Balb0wa over 9 years ago
seems to be 2m, id like a 20cm one :-) ,il have to get a crimper !
Posted by andrew (Favicon staff member) over 9 years ago
http://www.thinkbroadband.com/faq/sections/radsl.html#229

Hopefully people will read the FAQ and others like this one that the article does link to.
Posted by csimon over 9 years ago
Is that a reply to jelv?
Posted by CARPETBURN over 9 years ago
Anyone wanting a modem/router cable thats twisted pair thats good quality could consider one of these... http://svp.co.uk/product/masterplug_high_speed_modem_cable_(3m)_55071 its basically the same as cat5 cable with gold plated connectors.
If you need something a bit longer with some flexability i can recommend this http://svp.co.uk/product/high_specification_rj11_extension_reel_(10m)_5348 I have one which is 20M in length (they dont seem to have the 20M ones anymore though) and the quality both in performance and looks is superb, makes the flat cable you get with a modem look very cheap.
Posted by chrysalis over 9 years ago
thats cheap for what it is my belkin which is gold plated, twisted, shielded and is 5m cost about £10.
Posted by Somerset over 9 years ago
Amazing that buildings are cabled with CAT5 cable at 30p/m that runs 100M up to 100m.

Gold plated CAT5 connectors - complete rip off.
Posted by CARPETBURN over 9 years ago
^^^ errr so ARE you saying a pre-made cable with gold plated contacts which is 3metres in length from a branded known company for £1.02 is a rip off? LOL me thinks someone needs to visit places like PC world to learn the true meaning of rip off.
Sure anyone can make up their own cable from a cheap bit of cat5, but you will still need the connectors and the crimping tool, if you can get 3 metres worth of cat5, 2 rj11 connectors and a crimp tool for less than £1.02 im listening (could do with rewiring a few things :) )
Posted by Somerset over 9 years ago
£1.02 fine but not what Mr. Belkin charges!

I thought both part of a connector should be the same metal for the best connection.
Posted by 2doorsbob over 9 years ago
what alot of people dont realise is thay can use a single filter at home to protect all the phones in there home ..or a faceplate is even better coz if your phone extensions are hardwired faceplates have an idc terminal which is filtered..or you can simply fit a bt plug to your hard wired extensions ..i would recommend keeping rj11 as short as possible and use a longer ethernet lead
Posted by 2doorsbob over 9 years ago
i made my own rj11 up using cat5, about 2 feet was all that was needed
Posted by william963 over 8 years ago
I have had a really tedious 6 months of complaining to BT (via the Indian call centre) connection rates as low as 160kbps (fallback) the issue is because of a SKY Digi-box in a neighbours house this is typical of equipment not being Tempest proofed before going out to the customer. It may have 'approved by BT' so that it get's by the written inspections but appears not to be tested fully.
Posted by william963 over 8 years ago
If your connection is dropping and re-connecting at a low rate -it's probably a Sky digibox that's causing the problem - close by.
Mine was doing it for 6 months before it was found.
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