Establishing a network

The standard way to network several computers together is to put a network interface card, or Ethernet adapter, in each one. All of the Ethernet adapters are then cabled to a central hub. Other Ethernet-compatible devices, such as printers and high-speed modems, may also be attached to the hub - although you'll probably find it much easier to plug them into computers attached to the network.

If a network has only two devices, it doesn't need a hub; the devices may be connected directly to each other with a special cable, called a cross-over LAN cable. (The most common type of two-device system consists of one computer and one DSL or cable modem. See the "Running high-speed Internet access" section, later in this tutorial.)

Wireless networking, commonly called Wi-Fi or 802.11g (or the older 802.11b), has finally come of age. With the latest Windows XP drivers, wireless networks almost always get up and going in a matter of minutes, and the signals hold up amazingly well, even through several layers of concrete walls.

Many Ethernet adapters and hubs use a standard called 100BT or 100BaseT (pronounced one hundred base T), which theoretically can transfer data at 100 megabits (about 12 megabytes) of data per second (commonly abbreviated as 100 Mbps or 12 MBps). The latest Ethernet networks operate at gigabit, or even 10 gigabit speeds: One gigabit equals 1 Gbps, which is ten times faster than 100 Mbps. Realistically, networks never function at their fully rated speed, but some come close.

By contrast, older wireless networks work at 3 to 6 Mbps, and the new ones (the so-called 802.11g standard) go up to 100 Mbps. Wireless networks connect to hubs or routers - basically, radio receiving stations, which act like the base station of a portable phone - and the wireless base stations can, in turn, be plugged into Ethernet hubs.

Here's one way to put it in perspective. The text (not the pictures) of the 33-volume Encyclopedia Britannica would take

• A very long day to download over a fast dial-up modem. Maybe two, if your dial-up lines are as reliable as mine.
• 5 minutes to transmit over an older 802.11b wireless network.
• 30 seconds to go over a standard (100BaseT) Ethernet network, or a newer (802.11g) wireless network.
• 3 seconds to move over a gigabit network. Less than half a second on a 10 gigabit network. Or . . .
• About 200 years to print on my trusty little DeskJet.

That's a whole lotta data. You connect an Ethernet adapter to a nearby hub with a LAN cable that resembles the wire used to plug a telephone into the wall, although the LAN cable (called CAT-5) is thicker and the plugs on the end (called RJ-45) are wider. Over longer distances (up to 100 meters, or about 330 feet), you can use the same cable, but it needs to be installed with no kinks or bends - a job best left to an experienced CAT-5 or CAT-6 cable puller.

Tip Ethernet networking is a mature technology, and the devices are highly standardized. With few exceptions, you can mix different brands of hardware without compatibility problems.