Options: Technologies on the horizon
How to get faster, cheaper Internet access without a T1 or an ISDN line
WHAT IS IT?
Cable, digital subscriber line (DSL), or fixed-wireless technology
WHAT DOES IT DO?
All three technologies permit fast, cheap Internet access.
High-speed data communication has been available since the 1960s, first in the form of ISDN lines and then in the form of T1 lines. But the difficult installation of ISDN and the exorbitant cost of T1s (up to $3,000 per month for T1s, plus installation and maintenance costs) made both those technologies inappropriate for most small companies. Which is why many small businesses have come to rely on dial-up modems--devices that enable users to send and receive data over telephone lines.
The problem is, because of physical limitations in the lines themselves, dial-up modems transmit at top speeds of only 56Kb (as compared with a T1 line's 1.5Mb). ISDN, at 128Kb, is better than dial-up access, but not by much. Plain old telephone service (POTS), remember, was created for voice communication, not high-speed digital communication.
Enter the eminently affordable cable, high-speed DSL, and fixed-wireless solutions. Cable technology uses your existing cable-service provider to provide a link of up to 30Mb to the Internet. DSL technology utilizes unused higher frequencies on traditional (copper) telephone wires and your telephone company to connect, at up to 1.5Mb, to the Internet. And fixed-wireless systems use a series of antennae and/or satellites to send data at up to 2Mb to a wireless-telecommunications provider, which then links through a ground-based station to the Internet.
HOW DOES IT WORK?
The underlying connection method of all three technologies is the same: the telecommunications provider connects to both the user (via cable, DSL, or antenna) and the Internet. Users then access the Internet at high speeds through the provider.
For years cable service was a one-way analog medium: data streamed into the user's cable box, which in turn transmitted it to an attached TV. Now cable companies are upgrading their systems to allow data to be transmitted back to them along the same cable conduit.
Accessing the Internet via cable requires the user to upgrade an existing cable box and install a cable modem, which is generally the size of a regular dial-up modem. One end of the cable modem connects to the user's computer via a standard Ethernet network interface card (NIC) and the other to the upgraded cable box. Generally speaking, only one PC can be attached via the cable line to the cable box. However, by using third-party solutions, such as products from Ramp Systems, 3Com, and Cisco Systems, users can hook up more than one PC to the high-speed connection.
The upside to cable is its ubiquity: most homes in the United States already have the service, so gaining Internet access with the technology is easy. The downside is that cable lines serve not individuals but whole geographic regions. That means two things: security could be compromised, and bandwidth could be reduced. However, Internet-security devices can solve the security problem by admitting only the data that are part of a session initiated by the user. Products with such capabilities are available from Ramp Networks, Sonic Systems, and 3Com.
DSL employs unused higher (hence faster-moving) frequencies on existing telephone wires and upgraded equipment at the telephone company's central office (the facility that receives the connections for a specific geographic area and bundles them together for transmission to the main telephone system) to provide a souped-up continuous Internet connection. Many DSL modems must be installed by a telephone-company technician, but there are some, such as those offered by Netopia and Paradyne, that customers can install themselves. After the modem is installed, the user plugs a PC or LAN into it using a NIC. (LANs may require a router as well.) The user then switches the settings on the PC or LAN to those specified by the provider for Internet connectivity. Meanwhile, the DSL service provider places a DSLAM (DSL Access Multiplexer) in the telephone company's central office. The DSLAM will concentrate any DSL lines coming into the central office into a data network, which is then zapped over a massive high-speed wire to the central office's own Internet service provider.
A disadvantage to DSL, apart from the complexity of installation, is that the user's site typically must be within three miles of the telephone company's central office or else the signal will degrade significantly. An advantage, however, is that DSL is extremely easy to use because it's always on: once the user turns on the computer, the connection is established.