More ADSL/Phone Wiring Qs

[Bob Eager]

(long inaccurate rant)

Don't encourage him...!

[Huge]

He got round to it later.

[Dave Liquorice]

Total balls in the UK.

Relative to what? Is is "as soon as possible" after the demarcation point between the telephone network wiring (which you shouldn't mess with) and your own wiring (that you can).

This is a UK group hence, uk.d-i-y, and thus uses UK terminology. I suggest you make sure that a) you understand the terminologoy as used by this group b) that the practises your side of the pond apply this side.

Not over here. Use of "microfilters" for every bit of POTs kit has that effect.

Now that I do agree with. Which is what anyone, including BT, recomend as "best practice".

[w_tom]

splitter is mounted on the Master Socket or many are distributed throughout the building. Either way, faceplate splitters are a DSL filter with connection for DSL modem and for POTS equipment. Same configuration is used in Asia, N America, etc except the POTS connector is different. Where is the confusion?

[Steve Firth]

[much blather snipped]

I wonder which bit of "go ethernet ASAP" you failed to understand? Because the rest of the bollocks you posted was irrelevant.

[w_tom]

One posts well proven facts even demonstrated in Westinghouse and GE papers in the 1930s. Another proves knowledge using insults and words such as 'arse'. Clearly insults demonstrate grasp of technology.

A lurker can cry "woe is me" as Huge does. Or a lurker can learn even from BT who must not suffer damage even though connected to overhead wires everywhere in town. Huge speculates numbers for lightning and then knows BT must disconnect service during thunderstorms. Clearly no protector can provide protection. Huge says so.

Meanwhile earthed protectors are rated for many thousands of amps and higher. If Huge was correct, then BT disconnects all phone service during thunderstorms because those little protectors could not work.

[The Natural Philosopher]

The reality is that BT protects its own networks, not customer equipment

The reality is that most cables are underground these days, and poles are only the last 100 meters.

The reality is that most lightning strikes are not direct, and only induce a few KV at fairly high impedance into the wires. These are easily coped with by most equipment which IS fitted with surge suppression..and earthed.

The reality is that nothing will protect against a direct strike. In my case it burnt out 10 meters of overhead cable completely.

However it is instructive to look at what was subsequently damaged.

- the modem died completely.

- the serial parallel card it was plugged into died completely.

- the input board and the power supply board of a computer connected by a parallel cable to it does completely. The rest of the computer survived.

- an aerial socket connected to a bit of coax going nowhere except near the phone line, blew out the wall.

- so did a mains socket that proved to have never had an earth,

- I had scorch marks in some carpert where a twin mains flex light cable running to a light by the bed ran underneath it and a cable cobnnceted to a vacuume cleaner rand above it. It jumped from commons mode mains to the earth burning a 2mm hole in all the insulations and the carpet.

- The RCD tripped.

- The TV on standby failed - it wasn't worth fixing so I replaced it.

- My priceless revox parallel tracking deck stopped working. I got it fixed - IC gone.

My total spend was £75 for repairs and £75 for a new telly.

The phones - POTS - survived IIRC. I am not sure whether the asnwering machine did or not.

The printer and the modem were fixed under warranty actually. The US robotics modems had lifetime guarantees, and tehy wer happy to send me a new one. The HP laserjet did not, but the service engineer was a kind man.

I had no insurance.

My landlord did, and the insurance company insisted on a rewire. I didn't complain about that. ;-)

The final reality is that most manufactires of kit that is connected too telephone lines have a vested interest in making sure that it works through the average thunderstorm. Yes, a proportion of kit always fails after a bad one, but never high enough to give them bad press. And if they take the US Robotics view, they will replace it FOC anyway.

I know because I worked in South Africa, what persistent intense thunderstorms can do..but by bit we redesigned kit to take it till the returns and service calls got down to an acceptable level.

All I will say is that switching stuff OFF completely during a very very bad storm is wise..if the mains gets a strong surge, that will in general protect that kit..the surge will go where stuff IS switched on.. probably the fridges and freezers etc..and in general it will flip the RCD..a good reason to have an overall one as well as individuals.

As far as ADSL kit goes..well maybe you will blow it, but its got its own stuff in there anyway, and if you get a direct strike you can kiss it, most of your phones and a lot of other random stuff good bye. That is why you have insurance on house contents..

[Huge]

I'm not a lurker. You're patently a f****it, though. And a persistent one, judging by the comments made by others here.

Err, no. They're from the relevant British Standard, which has a graph of the current flow during a strike. The vertical axis is in units of kiloamperes, the horizontal in units of milliseconds.

Direct strikes to overhead cabling will result in you sweeping up the remains of your cables in the form of congealed droplets of copper.

Quite so.

[Steve Firth]

In your pointy little head.

[The Natural Philosopher]

Hang on a minute. *I* didn't say that - HE said it.

See..when you respond to ME we agree!

>

[Huge]

I know. The indents make that clear, but I apologise if you thought it was directed at you - you're not the FW, he is. I was replying to both of you - he's killfiled now, so I don't see his stuff directly.

[w_tom]

Exactly what was posted previously AND in direct contradiction to what Natural Philosopher had posted previously. Direct lightning strikes to BTs network (above or underground) and still BT equipment is not damaged. Protection from direct lightning strikes is routine. How often is phone service down for five days as BT replaces their switching computer due to lightning damage? Never. Surge protector does earth direct lightning strikes. Protection from direct lightning strike is not just possible. Protection is routine.

Same solution must be earthed at the subscriber's end of that network. Protection from direct lightning strikes - performed routinely in BT COs, where operator wear headsets while thunderstorms occur, commercial and cell phone transmitter sites, etc - it is about earthing every wire that enters a building. Proper earthing means direct lightning strikes without damage. That same protection is now required in residences that contain transistors (ie DSL modems).

Earthed protection from direct lightning was even demonstrated in a

1950s Bodle and Gresh study from the Bell System Technical Journal citing 100 strikes to each cable over 5 month period. Effective protection even when using 1959 protection technology. No damage from numerous direct lightning strikes is that common Protection is defined by what? Earthing. Damage may occur when the protector does not make that short connection to earthing. Damage from direct lightning strikes means the protection 'system' was not installed - a human failure.

[w_tom]

Huge demonstrates those who will post without first learning facts. He knows surge protectors are not effective only because he knows. That emotion is sufficient. How emotional? Notice his proof is provided in profanity and killfiles. As if we don't have enough extremists who just know - Huge also wants to join that list.

Meanwhile protection is routine if properly installed and as defined by solutions proven by generations of experience. A protector is not protection. The protector will only be as effective as protection it connects to. Protection is earth ground. Improperly earthing is one typically reason for electronics damage. Effective protector makes that short connection to earth. Single point earthing. Ineffective protectors will not discuss earthing for obvious reasons. If informed, then a consumer would not buy their product - that does not have a necessary and dedicated earthing wire. Reality expressed with technical facts, previously provided numbers, a long history of examples, the underlying concepts, and with no profanity.

[John Rumm]

You often find that if you attempt to run phone and modem on the same line they will work fine (assuming you have some DSL noise marhin headroom) until you take the phone on or off hook. That *does* create a burst of higher frequency noise due to the DC switching. That will often cause a loss of DSL sync.

A small proportion of handsets (especially the older non DECT cordless models) will also manage to demodulate some of the ADSL signal as hiss into the audio band of the phone. I have only heard this on about three installs (of hundreds) so far however.

[John Rumm]

Not really, they are all connected to the filtered side of it.

It is as soon as is legally allowed - where the line enters the consumers master socket. All wiring prior to that belongs to the telecoms provider and in theory should not be altered by the consumer. (not that many of us take much notice of that restriction of course!)

You don't use faceplate splitters at every phone. You have one and one only at the master socket. The terminology we use for the type of splitter one installs at each socket is a "plug in splitter" or "plug in microfilter")

Indeed. In fact the recommendation (if using more than one splitter) is to have no more than four[1] in total (although you can have as many POTS devices on each splitter as you want)

No, different terminology here...

< snip stuff all are in agreement with > [1] For filters built to ITU-T Recommendation G.992.1, See BT Document SIN 346 -

[David Hansen]

On Mon, 22 Jan 2007 11:26:05 +0000 someone who may be The Natural Philosopher wrote this:-

Indeed. My house is a few hundred metres from the telephone exchange, but the only overhead wiring is less than 20 metres to the pole which all the houses are connected to. From there a cable runs down the pole to underground cables.

That is a relatively old installation, newer ones are underground all the way.

[Brian Sharrock]

This must vary by location ... perhaps country? From my locale I can see two 'installation'. BT have placed a new pole in a street and connected existing houses to it. The poles are inter-connected by a cable at their tops leading to a connector box, then cables off to each house served. Down the ways ... an-old-bungalow-with-large-garden was renovated as a fourteen-dwelling estate with a 'posh name'; in this case a large pole was erected by BT in a corner of the 'estate'; connected with an overhead cable to an existing street pole then each dwelling is fed with individual cables. It all looks quite ghastly! Particularly as way-back the entire area was laid for cable with a, then , obligation for the franchisee to lay a duct ~ passing every dwelling ~ . The developed 'estate' doesn't seem to have such connectivity , to a casual glance. I suspect that the developer had an 'arrangement with a certain comms supplier to make it easy for purchasers to get connected from a certain supplier.

[The Natural Philosopher]

My supply comes underground..on the far side of the road.

I have my very own pole to take it across the road.

I COULD have got he road dug up and underground put in..at my own expense...

There is some overhead trunk in the village..but most of it is undergrounded.

BT and the power people say they are not putting in any more overhead trunks, but they do definitely add to what they have sometimes.

[tony sayer]

I think that the illustrate this argument better it isn't the "earthing" as such, but the "shunting" and "bonding" that is inherent in lightning protection systems so that no damaging potential differences exist that actually do the harm!...

[JohnDW]

...

...

John, I was also going to reply to w_tom's post since he appeared to negate all my experience. I then realised he was coming from a US wiring background so his comments were not correct for our UK wiring practise.

For the benefit of the OP and others in the UK, some of the comments of w_tom are not correct for the UK. We use the term "faceplate splitter" to refer only to the type of splitter we can install to replace the lower part of the BT master socket faceplate. This is the first place we can (contractually) install a filter to separate the telephone from the DSL signals.

In the US, faceplate splitters are simply replacements for any phone socket faceplate. They have inbuilt filters so all standard phone sockets faceplates can be replaced by ones with an inbuilt phone filter for a standard phone-type device. This type of installation provides little electrical improvement over the use of plug-in splitters. (OK, there is one less BT plug and socket used so that is an improvement)

If you use UK style pre-filtered telephone sockets, similar to

then you cannot fit them in place of the BT master socket. They can be used in place of user-installed secondary sockets instead of plug-in filters, if you want a neater installation. However, this is not the best solution, since you are still distributing the DSL signal around your house, where it can pick-up RF noise from the house, from switches, thermostats, and the like.

If you have an old BT master socket without the removable half front-plate, then you could install ONE of these pre-filtered telephone sockets next to it with a single wire pair from the old BT master to the new splitter socket (no pin-3 ring is needed). All your in-house wires would then be wired to the connectors in this new socket, instead of those in the old BT master. This will give an installation that is electrically similar to that using the faceplate splitter.