This error means that there is a problem with the modem getting an open phone line.

This could be a problem in your modem, your computer or phone line.

Try this step by step approach to solving the problem.

Step by Step

1. Plug a phone into the phone plug and check it's working.
2. Check that the phone line is plugged into the modem into the 'Tel' plug.
3. If you are using an extension phone line try swapping it for another and see if that works.
4. Try unplugging other phones in the house. (Look under your phones, answer machines etc for a sticker with their REN numbers. Add them all together. Most phones have a REN number of 1. You can have a maximum total REN number of 4 in a house which means most houses can have three handsets and a modem connected at any one time.)
5. Check that you do not have a voice mail system on the line. Services like BT's 1571 make the dial-tone beep and your modem will not be able to dial. Contact your telephone company to find out how to switch this off. Or, get all your messages before you try to connect.
6. Put a comma in front of the number you are dialling. This will make your modem pause a few seconds before dialling. This may help if there is a delay in the line giving a dial-tone.
7. Try re-installing your modem's drivers and then test the modem. To get the latest driver for your modem visit your modem manufacturer's website.