When a reader contacted us to tell us his broadband connection worked only when he lifted the receiver on his phone, our Helproom Editor explained that it was probably a problem with an ADSL filter. Here's how to fix broadband that works only when you lift up the phone.

QUESTION I'm unable to connect to the internet unless I pick up my phone. I haven't changed any settings. I've tried restarting everything and have checked that it's all correctly plugged in. I also note that my phoneline is crackly, but BT wants £100 to come and check it for me. Can you help?

HELPROOM ANSWER First, rest assured that you won't receive a large repair bill. BT charges customers only if one of its engineers has to waste their time coming to your home, only to find no genuine fault. Since your problem can be easily demonstrated, this will not happen.

If your broadband is working fine only when your phone is off the hook, it could be a problem with your ADSL filter, or this could have been inadvertently removed. Also, if you've added a second phone anywhere else in the house, it will need its own ADSL filter to prevent interference with the internet.

Try unplugging all the landline phones in the house. If the problem goes away, it's either a faulty phone or the lack of an ADSL filter that's causing the problem.

This video shows you how to check your wiring by accessing the test socket in your master socket.

If your broadband connection is reliable enough, also try BT's free line test service. This will automatically test the line, and an engineer will be despatched if a fault is found.

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