If your broadband internet isn't working, and you've checked with your ISP that the line is fine, there are a couple of things you should try.

This article appears in the May 07 issue of PC Advisor, available now in all good newsagents.

Telephone intruder

Ensure that every phone handset has an ADSL microfilter between it and the phone socket. Unfiltered connected phones can disrupt your ADSL signal and, if you lose your ADSL connection when the phone rings, there's a rogue, microfilter-less phone in the house.

Check that your microfilters aren't faulty, if necessary swapping them for known good ones. If you have to, unplug every phone (and microfilter) in the house, leaving only your ADSL modem plugged in. If you can then successfully get online one of the phones or microfilters is defective.

Essential synchronisation

If your modem or router can't synchronise with the DSLAM at the exchange then this will typically appear as an unlit status LED – possibly labelled Sync, ADSL or WAN. Synchronisation is essential for you to have an active and working ADSL line, but note that this isn't related to your ISP connection. So, if you don't have sync, you won't be able to connect to anything.

Possible causes are: an exchange fault; ADSL not yet enabled; ADSL ceased or cancelled; faulty microfilter; faulty modem or router; poor line quality – noise, electronics, or a short on the line.