15. Try a “BT” Speedtest

BT Wholesale based ADSL customers may find it helpful to run the operators speedtester a few times. This one will forward the results onto your ISP and may help to identify any problems or improve the connection (tip: do some when you’re suffering from slow speeds and at different times of the day). Most UK ISP's are BT based, although not all lines use BT's service:

http://speedtester.bt.com

It is also possible to exclude your ISP’s network from the test by temporarily switching your username to “speedtest@speedtest_domain” and reconnecting. Once complete you should attempt to visit the same webpage again and run the test. The results could help to diagnose how much of an impact your ISP has on the connection.

Sadly this is only useful if you’re running off an ISP that utilises BT Wholesale’s broadband network, not unbundled (LLU) ISP’s or different broadband technologies (satellite etc.).

People using BT's latest ADSLMAX / ADSL2+ based IPStream service (i.e. an 'up to' 8-24Mbps packages) may run into problems with the above 'ISP exclusion' test. Related users should instead try connecting to the old tester via the following URL (same login details should apply, if not then try 'startup@startup_domain'):

http://217.35.209.142:50302/cgi-bin/home.page.pl

16. Try “BT’s” test login

Having problems connecting to your BT Wholesale based IPStream ADSL ISP? One useful check is to try the operators test login. Just change your connection username to “bt_test@startup_domain” (lowercase characters) and reconnect (no need to alter your password), if you’re able to visit the “http://www.bt.net/digitaldemo” website then the problem may be with your ISP.

Thankfully it’s also possible to use the test login with your ISP’s side of the connection too. Instead of replacing your username with “bt_test@startup_domain”, use “bt_test_user@ISPs_domain”. Typically the “ISPs_domain” part should be replaced with the domain of your ISP’s username. For example, a Nildram customer might have “IanWatson2@gotadsl.co.uk” and thus you’d need to input “bt_test_user@gotadsl.co.uk”.

Sadly unbundled (LLU) providers or those based off BT’s Datastream technology may not be able to use this; however such ISP’s often provide an alternative method. For example, Tiscali uses a username of “testing@dslconnect.co.uk”, although you’ll also have to enter a password of “testing”. It should then be possible to visit the http://speedcheck.ispconnect.co.uk website.

17. BT’s Automatic “quiet line [noise] test”

BT allows you to conduct an automatic “quiet line test”, though it may not identify all sources of line noise. Simply dial 17070 and select the appropriate option (usually number 2); it’s worth doing this for all of your phone extensions. If there is anything other than silence, report it to your phone provider, if it is clear, then it is most likely an ADSL fault or other problem.

It is also possible to dial 150 for a line noise check but don't mention that this is for broadband/ADSL, otherwise they will pass it back to your ISP and that could result in additional costs.

Please be aware that these tests are designed for BT lines (i.e. might not work if your line is not managed by BT). Fully unbundled ISPs may have an alternative test that you can try, contact them to find out. If in doubt, try the BT test first.

Something you could also try is to walk around your home with a corded phone and try plugging into the different sockets (all should have microfilters on) to see if the crackling is the same in each. It might just be a problem on particular sockets due to a primary junction wire having come loose behind one of the faceplates.