BT Line Tests (quiet line/distance from exchange etc)

Hi,

Since people often mention the 'quiet line test' or ask 'how do I find out how far I'm away from the exchange', here's some simple instructions

The BT line test facility can be accessed from any BT (or WorldOnline) line by dialling 17070.



Quiet Line Test

Unplug any extention phones, extention cables, answer machines or fax (anything except the phone you will use to do the test!).

Plug a normal touch tone phone directly into the BT master socket.

Dial 17070, press option 2 (quiet line test)

You should hear 'Quiet Line Test' and then silence, there should be no pops, clicks, whistles, buzzing etc. If there is noise on the line, make sure it's not your phones connection to the socket (wiggle it about a bit) and that you are using the master socket. If you are sure its the line making the noise then dial BT (or WorldOnline) and report the fault, they should be able to sort it out. Remember that 'mis-reporting' a fault (e.g. if it turns out to be your phone, extention cord etc.) may be charged a call-out fee by BT (/WOL).

any probs? see It doesn't work? (below)



Distance From Exchange

Dial the same line test number as the quiet line test (17070). Then press option 3 (fast test) then press option 1 (to say you are authorised, don't worry about 'not being officially authorised'). The press option 2 (ring back test). Then put the phone down.

You will get called back by the test facility within about 10 seconds, one of the bits of information given will be distance from exchange (in kilometres).

*The distance result may not be accurate if you have a 'DACs' fitted. It is not 100% accurate but does serve as a guide.

any probs? see It doesn't work? (below)



It doesn't work?

You need a BT line (or WorldOnline).

You need to use a touch tone phone (don't think it works without one).

You have caller line id (CLI) blocked, if this is the case then on dialling 17070 the message will include 'there is no CLI detected for this circuit'. You can get round this by dialling a prefix before 17070, the prefix is 1470, so the full line test number will be 1470 17070.


Sil

Just re-reading, I realised that this b4 but to add.

If after you've done your quiet line test and everything appears to be fine, go back an repeat the test with everything plugged in (ie as you would normally operate your modem). So for instance if you need to use a telephone extention cable to connect your modem to the phone socket, plug the phone into that an repeat the test (try wiggling the connections a bit to see if it introduces noise). If noise is introduced then by process of elimination you should be able to track down whats causing the interferance.

I had a problem with bad connections which turned out to be the phone extention cable, switching it for another one cured the prob

Sil

Hi Sil

I tried the "quiet line" test - which was okay.

I then tried the "distance from exchange" one, and on each occasion got three different answers :

1) 918 meters
2) 922 meters
3) 920 meters

What does that mean I wonder

Is my local exchange "floating" on some very large patch of water and keeps drifting away then getting pulled back in by the tide ?



I don't understand how it reports a different distance each time I ring it up ?

Any technical people out there then please ?!

wow you're close the the exchange you should get a decent connection

It estimates it using some 'phone network magic'

Sil

Hi again Sil !

Never mind the magic, I think someone has put a curse on me and my net connection

If, as you say, I live that close to my local exchange and should get a decent connection....,
then why don't I ?

FYI - the line distance test should be carried out 3 times and the average taken. That's the way BT's engineers do it, at least.

Thanks FastShow, good advice

Sil

I tried the advice posted advice to run the second test (to find my distance from the exchange).

The first part worked and I got phoned back but unfortunately when I answered the callback all the automated voice said was "line is ok". No other info like distance from the exchange.

Any ideas why?

Hi gebbly,

I pressed '3' (fast test) then '1' (authorised) then '2' (ring back test).. it phoned me back and said it couldn't test the line and I should phone the controller or something. Normally it works (or at least it used to work!). Perhaps try again in a few days?

Sil

PS., welcome to TS!

I tried this and although I don't withhold my caller ID, it still did not work until I dialled 1470 beforehand. When I got the ringback all it said was line ok with no information on distance

It would appear the distance test now only works on some exchanges, either by accident ot design..

Does anyone know if BT have moved the goalposts recently for line length because a month ago my line length was on the limit and I may able to get it, now it says I am too far away and can't have ADSL!

I have just had my line repaired due to noise and they swapped my line this could be the reason? Or is irt because my line was rejected before because of the fault?

Hi,
Just thought I'd let you guys know - BT have now removed the part of the 17070 service that tells you your distance from the exchange, due to the number of people using it to complain about their broadband
You may find that it still works on some exchanges..

This doesn't affect any of the other services on this number, ie the quiet line test.

-:Toast0r:-

ps. not that its really relevant now, but the reason that 17070 sometimes returns a slightly different distance each time you use it is because of the
formula thing that is uses to calculate the distance. don't ask me how it works though lol

All to do with the resistance of the cable, longer the cable higher the resistance.

Bummer them killing that off, am about to move and wanted to test the place first.

~Mem

not sure it uses resistance, I thought it sent some kind of signal and timed how long it took to come back - could be wrong tho!

Sil

PS,. Welcome to TS! Toast0r and thanks for the info

Must admit I thought it was a signature test where by a hex signature is sent down the line and then echoed back ?

'Slo

you mean like a ping test?
whats echoing it back??????
the phone doesn't, afaik

~Mem

a phone line is a loop, as far can I can remember (back in the days when...) hence loop disconnect dialling, it sends something down one way an times how long it takes to come back, perhaps?

Sil

I think Sil has got the jist of it.. its something along those lines anyway (no pun intended - honest). It was all explained to me a long time ago, but I really can't remember. Hey, as long as it works..

There are a couple of other ways to find out if you're in range.. one of the easiest (but most innaccurate ways lol) is the webpage (apologies if someone has already posted this - i'm sure they must've by now..) that BT run:

http://www.bt.com/btbroadband/ns_ava...K&obsOID=30535

(Its a really stupidly long URL.. I asume this forum script will shorten it. If not then grr)

Another way (and more accurate) is via a certain phone number. I don't have it to hand, but I will try and get hold of it. Alternatively, if you go into any Maplin Electronics store, pretending that you want to buy their 'Broadband in a Box' product (BT based) then they will call the number for you thinking they might get a sale (bwahaha)
They will then tell you yes or no. Obviously you don't have to buy it from them whatever the outcome.

Memfis: If you want to try this on the house you're moving into, then you may well need the postcode..

Have fun

-:Toast0r:-

related subject - you know the ringback and quiet line tests? Is there any similar test you can do on ntl and telewest lines? My ability to search google has let me down on this one. Thanks.

You'd think there would be.
But I've never come accross one. Due to the way that NTL and Telewest provide the service, they may not be able to provide a line test facilty I guess. I'm sure someone will correct me in a few posts

I'll ask around.. no promises though.

-:Toast0r:-

Yeah, but I wont have a net connection.

Gonna have to ghit the cafe's

~Mem

Hi, I've been trying for adsl for a while now. I was 5.4km away from the "enabled" exchange but now since they extended the workable distance to 6km, apparently I've moved! "Sorry" it will only work if I'm less than 6km. Currently I'm running ISDN.
If I enter the 2 ISDN numbers I "may be able" to receive it.
I did the noise test and couldn't hear a thing! Last time I applied they said too much noise.
Any ideas?

Thanks

I did use that link for the broadband a while ago, line check etc. Ordered the broadband, and then a day before it was due to be activated got an e-mail saying it wasn't available and the order will be cancelled. Of course, BT couldn't provide a good answer. Was wondering if it is maybe because we changed our telephone company to Reach, or something like that.

What do they mean 'not avaiable'? That's like saying it's not available on your exchange! That can't be correct, it must have failed one of their tests, I'd press them for an answer.

My exchange was recently upgraded but despite being only 2 miles from the exchange BT seem to think I live over 6.5km away. What I'd like to ask is does anyone know how to contact BT to get my line retested. Currently I have several irons in the fire but very little action. I have lodged a "complaint" with an operator in Newcastle; I've asked my future(?) ISP to talk to BT Wholesale; and I've requested a home visit from an engineer (this will probably cost me an arm and a leg!). Any other ideas? The galling thing here is that when I use my neighbours' phone numbers to check availability they can all get the service.

Welcome to The Scream! Mr-M.

One thing we don't know(?) is HOW they measure the distance. Is it simply as the crow flys or is it how long the cable is from your phone to the exchange. It MAY go some VERY abnormal and long route. But I don't know!

Anyway, I DO hope that you get ADSL SOON! I've (well, we actually - me, the wife and two sons) have enjoyed ADSL for around 3.5 years now.

The distance is line distance.. well that's what's important anyway.

If you neighbour can get it perhaps they can do some re-routing?

Good Luck!

Sil

Found This

TDRs can be used to analyse the reflective properties of wires and cables. The basic
principle is to feed pulses of short duration into the cable and view the reflection of the
pulses by means of an attached oscilloscope. Splices, taps, short circuits and open ends
will cause different behavior concerning reflections and thus can be distinguished from
each other. The time between the transmission of the pulse and the reception of
its reflection can be read from the oscilloscope screen. Knowledge of this time makes
it possible to estimate the distance to the location where the reflection occurs.
Professional TDRs are expensive, but a simple TDR pulse generator can be home
made for about $20. In addition to the pulse generator a fast oscilloscope is needed,
which can be quite expensive itself.

Hi All,

I know this is an old thread, but I have an issue that may be resolved by calling BT (though I seriously doubt that), but need some clarification.

I want the O2 broadband package and when I put my postcode in, I get told that there is great news, and I can get their service. When I enter my phone number however, boo hoo, no broadband available. Apparently this is because I am over 4km from my exchange. The house I live in is only 3 years old, and I can't believe that I am 4km from the exchange unless my phone line is routed via BT's Indian call centre for troubleshooting purposes.

As the postcode returns a positive result, and the phone number returns a negative result, can I get BT to re-route my phone line? Or could I change the number to get it re-routed?

Cheers in advance