Here are some steps to follow to work out whether your phone line is playing up, your ISP is overloaded, or we've lost our overseas cable with the rest of the world.

Let's look firstly at what our modem does. Once we've pressed the Connect button in the Dialup Connection box, our computer dials our Internet Service Provider's modem number through the modem. Our ISP's modem answers (hopefully) and both modems talk about the quality of the phone line. After negotiating a speed at which to communicate - more often than not, an over-optimistic speed - both modems are ready to pass information up and down the phone line.

Once the modems are talking, the little screens icon appears in the system tray at the bottom right of your screen. This is the one that flashes when data is being received or sent by your modem. Hover the mouse over this icon and you'll be told the speed at which your modem has decided to try to talk to your ISP's modem. Or you can double-click this icon to bring up the Connected to YourISP message box to read the information.

With most computers having their modem on a board inside the computer, that's all the information you can get. On the other hand, if you have an older, external modem, its lights will tell you the connection speed and you can periodically glance at it to watch for any changes in speed - usually, to a lower value (remember, the modems were probably over-enthusiastic when they set the speed they could talk to each other).

So over a period of time you get a feel for how fast your modem works. One day, however, everything slows to a crawl. Has your modem decided to take a sickie? Most likely not, unless your phone line has been hit by lightning (a rare event around here at present). It could be that your ISP's computers are being overloaded by users, or we've lost some overseas capacity because of some fault in the overseas cables.

To work our way through the possibilities, firstly check your connection speed. Let's assume it's about what you normally expect. Are you online at about the same time as normal? If, for some reason, you've tried to go online just after school has finished, perhaps all the school children have come home and gone online. To eliminate the possibility your ISP's computers are extrememly busy, try connecting at a later time.

On occasions the overseas cables suffer a fault and that means we can't access overseas sites, particularly those in the U.S.A. To eliminate this possibility, try a site your know is in Australia. For example, try browsing your ISP's home page or the ABC or one of the newspapers.

Now we come to the final option. Firstly, if you can't connect, that is, your modem is unable to dial the number of your ISP's modem, there's most likely a problem with your phone line. It's certainly the case if the last time you connected, just the other day, everything went smoothly. The modem can be eliminated as the cause since lightning is about the only way it can be destroyed (or a hammer, in the extreme!).

In effect, a modem is a good measure of the performance of your phone line. If the connection speed suddenly drops off, compared to previous days when you've connected, something has happened on the phone line. That means it's time to report a fault.

Remember that your modem can't be slowed down to cater for a poor phone line. Your modem and your ISP's modem negotiate the quality of the line when you attempt to connect, and if the quality of the line is not up to standard, they will decide there's no point in talking to each other and will disconnect.

Finally, a number of sites offer modem speed tests and, to a certain extent, they at least give you some assurance about how you might feel your line is behaving. Try the one at BandWidth Place at www.bandwidthplace.com/speedtest/.