A simple telephone line quality test for ADSL (UK only)
When installing ADSL services it is always handy to be able to run a very simple test on the phone line. This test is not the most scientific, and relies on the sensitivity of the human ear, but it works great.
Learn about some simple engineer tests you can perform on your telephone line.
Before I go any further I need to point out that this test is for British Telecom (BT) analogue phone lines in the UK only. There are likely similar test services out there for other services, but I don”t know of them.
Testing from the local exchange to your building.
In order to rule out interference from inside the building it is important you test at the master socket. This socket is where the copper pair from the street enters your house. You can remove the front panel from the master socket which will disconnect all extensions in your house and reveal a single phone socket. This phone socket is a direct connection to your street.
Connect a good telephone into your master socket and dial 17070.
At the time of writing you hear a female pre-recorded voice say:
This circuit is defined as 01234 123123.
BT line test facilities.
Please press 1 for ring back, 2 for quiet line, 3 for fast test, 4 for fast cleanse or clear down.
[message repeats 3 times]
Select option 2 (quiet line) and listen to what you hear. You should hear perfect silence on the line – there should be no pops, clicks, whistles, buzzing and the like. If you do not hear silence first check it isn’t the phone you are using, wiggle the cable a bit to see if that affects it, if not then you know you have a problem with your line to the BT exchange. Any problems with ADSL connectivity (low speed, connections always dropping, etc) are likely caused by this.
You can now put your master socket together again and re-enable all the phones in your house.
Testing the internal wiring of your building.
So you’ve performed the test at the master socket and all sounds good.
Now you can perform the exact same test again, but this time with a phone where your ADSL modem would connect in. This should include any and all telephone extensions you intend to use.
If you hear noise on the line now you can deduce that the interference is coming from inside your house.
Things to check for are telephone cables running near transformers or motors and compressors, faulty equipment on the line introducing noise. Hopefully by removing equipment and tracing back the line you will be able to identify the source of the noise and replace/remove it.
How far from the local exchange are you?
The BT line test facility allows you to obtain your distance from the exchange. To do this dial the same line test number (17070), select option 3 (fast test) then option 1 (to say you are authorised). Then press option 2 (ring back test) and replace the handset.
After about 10 seconds you will be called back and one of the pieces of information returned will be the distance from the exchange (in kilometres). I understand BT engineers normally repeat this test 3 times and take an average. The results itself are calculated by sending a low amplitude high frequency signal down your line and listening to the farthest reflection (at your house) – therefore they are likely to vary by 100 meters or so.
The number doesn’t work for me, all I get is ”There is no CLI detected for this circuit”.
This means you have Caller ID blocked on your line. To get around this dial instead 1470 17070.
October 25th, 2008 at 6:53 pm
i have tried and tested the above, and yet i still have no dialing tone, nor anyone speaking to me from the other end of the test line, but i still have my internet connection, what else could i try to get my phones working again, i have been and bought a new phone thinking it could be the old 1 i was using, but it still does not work.
November 8th, 2008 at 6:20 am
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November 25th, 2008 at 1:51 pm
Fast test has changed now and now requires a pin or authorised mobile phone number. Shame.
June 9th, 2009 at 7:01 pm
17070 and 2 quiet test proved I had a fault which bt did not originally agree was the case. Thanks
June 9th, 2009 at 7:11 pm
Great news Rex – I’m happy to have helped.
August 1st, 2009 at 8:17 am
Dry joint problems can be intermittent and commonly occur during hot weather, (heven knows why the problem persisted in July 2009!)
If you hear noise on the line, switcjhing on the ADSL modem fequently increases the noise once it has found the internet connection. This is a result of the ADSL HF signal being rectified by the noisy joint and NOT a fault of subscriber’s equipment.
August 1st, 2009 at 9:20 pm
Glad i found this as im having a major problem with noise/static on the line that increases badly when the router is syncing in at the exchange. BT have run tests that say the line is ok, which i know it isnt, and ive had an engineer up this morning who did nothing other than run the quiet line test on my phone and stated that as it was a clear line he wasnt going to check for any fault. Im now trying to get my ISP to get this problem sorted and to be honest they are doing nothing much about it so im stuck with what to do next.
August 1st, 2009 at 9:25 pm
Hi D Parker.
Unfortunately most ISPs are useless and won’t fight your corner for you.
Have a look at an ISP called Andrews & Arnolds (www.aaisp.net.uk) – they will guarantee to fix any problem you have and will badger BT about the problem until it is fixed. It’s who I use and they are currently fighting BT for me atm.
Good luck.
August 10th, 2009 at 8:32 am
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August 27th, 2009 at 8:17 am
Very timely (for me) post, Thanks.
One thing though … How can one get out of test loop, still getting broken dial tone?
September 12th, 2009 at 8:05 am
Be careful. I did this and there were two faults found between my house and the exchange. The engineer fixed the noise on the line by changing from one cable to another. Much better sound quality on the old phone. BUT my broadband speed has reduced from 4M to 1.8M. The new cable he used has a higher signal attenuation (63,5dB instead of the old one at 45dB). I now reported this as a “fault” and may have to pay to get it fixed!!
January 2nd, 2010 at 11:34 am
After using my wireless phone, either incoming or outgoing call, and putting the handset down, the phone rings twice after approx 30 secs but there is no caller.
I have adsl and the internet is ok.
Any suggestions please.
July 1st, 2010 at 6:27 pm
Has this 17070 number changed?
just tried it but doesnt work?
January 31st, 2011 at 9:30 pm
The 17070 number still works, but I only get the first line of the message i.e.
This circuit is defined as 01234 123123. (repeated 3 times)
Then it cuts off. There are no options.
March 12th, 2011 at 2:39 pm
Does anyone know how to check the incoming pair at the master point. I’ve taken mine off and have four wires coming from the street and cant remember which two it is? Any help would be great.
March 13th, 2011 at 9:50 am
just done this test and it good idea instead of ringing the phone company to test it for you
June 20th, 2011 at 4:20 pm
Hi there,
my phone line stops working when it gets hot – about 23 degrees. It’s happened 3 times in the past 3 months, and service comes back when the weather cools down, at which point BT think they have fixed it. They can’t seem to comprehend that this is an intermittend, recurrent fault, so every time it happens they treat it as if it has never happened before. Any ideas?
Thanks, Karren
June 20th, 2011 at 4:44 pm
Hi Karren,
I had something similar where my line would drop for 5 minutes roughly once every 2 hours on cool days, and as often as once every 40 minutes on hot days. It turned out it was a piece of faulty equipment in my local exchange – but it took many months to get BT to repair the fault. In the end I did it with my broadband provider (Andrews and Arnolds Ltd) who had a business-to-business relationship with BT and could keep throwing the fault back at them. I understand your frustration with BT – I had a fault about once every 2 hours and they’d book 40 minute windows for engineers (so they’d likely not witness it happening).
It is possible that heat is causing a connection somewhere to expand and contract, and breaking contact about 23+ degrees. It might be worth checking all the connections in your house just in case it is there, but it could just as likely be on a pole or at the exchange.
In my experience the BT engineers are nice guys mostly, offer them a cup of tea and a biscuit and they’ll do a pretty good job trying to help you out. The problem is with the numpties in the call centers scheduling their work and forcing them to flit between jobs before they’ve had time to fix the problem.
June 21st, 2011 at 11:05 am
thanks for the advice. the engineer came this morning and fitted new cable where it enters my property. he diagnosed noise on the line, and told me how much prssure they are under… all the problem i’ve had have been at the so-called customer service end. i think it’s all sorted now.
July 4th, 2011 at 5:05 pm
Hi, We experienced very loud crackling 10 days ago, followed by a dead line. I have run the usual tests with two different basic telephone apparati straight into the test socket. Our telecoms reseller’s call centre just give us the same blandishments each day about an exchange fault under repair, but a BT engineer I know tells me it can’t be, and is almost certainly a fault between us and the road. We run a small business from home so are desperate; I am now working in my fourth borrowed office space. Unfortunately our line rental is also with the reseller. How can we apply pressure to get this fixed, or at least get a sensible date? Thanks, Richard.
July 4th, 2011 at 5:55 pm
Hi Richard. The fastest method I know of would be to immediatley switch your broadband to Andrews and Arnolds (www.aaisp.net.uk) and speak to their tech guys. I’d give them a call – they even have some offer where you don’t pay anything if they can’t fix your fault.
July 4th, 2011 at 5:59 pm
I’d just like to say I am not in any way affiliated with Andrews and Arnolds – it’s just that most questions on here are broadband faults and they are genuinely the best people I know to help you.
I should be on commission though
July 4th, 2011 at 6:02 pm
Hi Neb – I know I’m late replying, sorry.
It’s normally the Orange and White pair. The other two wires are a seperate pair incase you ever require a second phone line.
White is considered “A” and orange is considered “B” when wiring to a master socket.
October 30th, 2011 at 8:58 pm
Has anyone else actually used aaisp.net.uk?