Most computers, especially ones in the home, connect to the Internet via the telephone network. You use a device called a modem to connect your computer to the phone line. Some computers have built-in modems and can be plugged directly into the phone socket; in other cases the modem is separate. Using a modem, you can connect to the Internet via a normal phone line. The modem dials the phone number of the Internet Service Provider (or ISP for short).
There are also high-speed Internet connections, sometimes known as broadband. These services are faster than the connection available on a standard phone line, so information can be downloaded more quickly. They normally use a specially adapted phone line. High-speed Internet access is sometimes provided by cable television companies, who use the same cables that carry the television signals to carry Internet data too. Even very remote places can be connected at high speed to the Internet via radio signals, sometimes bounced off satellites orbiting the Earth.
Engineers are also working on ways of carrying Internet data via power lines, so that in the future any building connected to the electricity system could also have a high-speed Internet connection over the same wires.
Very soon you may be able to wander around with portable computers that are permanently connected to the Internet without any cables. There are already computers on sale that have wireless devices in them. At the moment you need to be near to a wireless access point to use them. Some businesses, such as cafes and hotels, provide these wireless access points, so that their customers can use their own laptop computers to connect to the Internet without needing to plug in any cables.
Some mobile phones can already connect to the Internet, although the cost of doing this is too high for most people at the moment. These mobile phones can be used for sending and receiving e-mail as well as viewing Web pages on their screens. They can also connect a separate computer to the Internet.