Getting Connected: Modems

DSL (Digital Subscriber Line), a high-speed or broadband technology, has become increasingly popular. A DSL line remains connected to the Internet, so you don't need to dial up when you want to go online. Typically with DSL, data is downloaded to your computer at rates from to 1.544 Mbps to 512 Kbps; you can send data at 128 Kbps. Since a DSL line carries both voice and data, you don't have to install another phone line. You can use your existing line to establish DSL service, provided service is available in your area and you are within the specified distance from the telephone company's central switching office.

DSL service requires a digital modem and a network card in your computer. Prices for equipment, DSL installation and monthly service vary considerably, so check with your local phone company and Internet service provider. The good news is that prices continue to fall. In the U.S., expect to pay under $25 a month. Some companies now provide free installation and equipment when you commit to a year of service. For a detailed description of how DSL works and all the variations of the service, visit The Fast Guide to DSL.

Cable Modems

Another option is high-speed Internet access via cable TV. With speeds of up to 36 Mbps, cable modems download data in seconds that might take fifty times longer with a dial-up connection. Because it works over TV cable, it doesn't tie up a telephone line. Best of all, it's always on, so there is no need to connect and no more busy signals! This service is available throughout the United States, Europe and Asia. For an in-depth tutorial, visit How Cable Modems Work.

ISDN service is an older, but still viable technology offered by phone companies in some parts of the U.S. ISDN requires a so-called ISDN adapter instead of a modem, and a phone line with a special connection that allows it to send and receive digital signals. An ISDN line has a data transfer rate of between 57 Kbps and 128 Kbps. You have to arrange with your phone company to have this equipment installed. For more information, take the ISDN tutorial.

Leased lines come in two configurations: T1 and T3. A T1 line offers a data transfer rate of 1.54 million bits per second. A T1 line is a dedicated connection, meaning that it is permanently connected to the Internet. This is useful for web servers or other computers than need to be connected to the Internet all the time. It is possible to lease only a portion of a T1 line using one of two systems: fractional T1 or Frame Relay. You can lease them in blocks ranging from 128 Kbps to 1.5 Mbps. The differences are not worth going into in detail, but fractional T1 will be more expensive at the slower available speeds and Frame Relay will be slightly more expensive as you approach the full T1 speed of 1.5 Mbps. A T3 line is significantly faster, at 45 million bits per second.

Leased lines are expensive and are generally used only by companies whose business is built around the Internet or need to transfer massive amounts of data.