These systems will not support data transfer and will cause problems when you try to use them for your computer. To see if this is a problem, run a long telephone line from a standard socket to your computer. Also, some answering machines will also cause problems for your computer. To test if this is causing the problem, remove the answering machine temporarily and see if the modem will dial again. Remember, modems will fail and need to be replaced.
Nothing is more frustrating, but it does happen.
If you need to replace your modem, we recommend that you get a brand name. The better the modem, the easier they are to install and the better they are for reliability.