What is the difference between DSL and cable modems?

DSL provides always-on high-speed Internet access over a single dedicated telephone line; cable modems are the primary competitor to DSL and offer always-on high-speed Internet access over a shared cable television line.

There are two types of cable modems. The most prevalent is the hybrid fiber/coax (HFC) modem, which runs over HFC cable networks and offers theoretical download speeds from 3 to 30 megabits per second; however, real-world data indicate that you can expect speeds from 400 to 1440 kilobits per second.

The other, older type is a one-way modem that runs over standard cable coaxial networks. These modems offer up to 2 megabits per second download speeds, but they offer no upload capacity because cable networks were not originally designed for two-way communication. With the older system, if you need to send out information over the Internet, you will likely need a separate phone line, modem and ISP. This one-way approach is being dumped as cable companies upgrade to two-way infrastructure.

Cable networks differ from DSL networks in their basic structure. Cable modem service is set up like a local area network (LAN), making it possible for many users to share the same bandwidth. While cable modems have greater downstream (from the Internet into the home) bandwidth capabilities, that bandwidth is shared among all users in a neighborhood, and will therefore vary, perhaps dramatically, as more users in a neighborhood get online at the same time. The downside of shared access is security -- experienced hackers may be able to break into other computers on the same cable network in the neighborhood. Also, Cable modem upstream (from the home to the Internet) traffic will in many cases be slower than DSL, either because the particular cable modem is inherently slower, or because too many people in a neighborhood are trying to send or receive data at the same time.

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	In order to view the tariffs, you must have the Adobe AcrobatReader.		What is the difference between DSL and cable modems? DSL provides always-on high-speed Internet access over a single dedicated telephone line; cable modems are the primary competitor to DSL and offer always-on high-speed Internet access over a shared cable television line. There are two types of cable modems. The most prevalent is the hybrid fiber/coax (HFC) modem, which runs over HFC cable networks and offers theoretical download speeds from 3 to 30 megabits per second; however, real-world data indicate that you can expect speeds from 400 to 1440 kilobits per second. The other, older type is a one-way modem that runs over standard cable coaxial networks. These modems offer up to 2 megabits per second download speeds, but they offer no upload capacity because cable networks were not originally designed for two-way communication. With the older system, if you need to send out information over the Internet, you will likely need a separate phone line, modem and ISP. This one-way approach is being dumped as cable companies upgrade to two-way infrastructure. Cable networks differ from DSL networks in their basic structure. Cable modem service is set up like a local area network (LAN), making it possible for many users to share the same bandwidth. While cable modems have greater downstream (from the Internet into the home) bandwidth capabilities, that bandwidth is shared among all users in a neighborhood, and will therefore vary, perhaps dramatically, as more users in a neighborhood get online at the same time. The downside of shared access is security -- experienced hackers may be able to break into other computers on the same cable network in the neighborhood. Also, Cable modem upstream (from the home to the Internet) traffic will in many cases be slower than DSL, either because the particular cable modem is inherently slower, or because too many people in a neighborhood are trying to send or receive data at the same time. Return to previous page.
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