How do computers talk to each other?

Ethernet is a standard protocol that allows any number of computers to communicate with one another. A very simple way to connect computers is through Ethernet cable, or "Category 5" wiring. The Ethernet protocol is also used when computers communicate wirelessly (wireless connectivity will be covered later in this section.) Similar to a phone line, Ethernet cables can have from four to eight wires, as many as double the amount found in a phone line.

Ethernet cable is usually a bit thicker than a phone line, and the jack looks like an oversized phone plug. Even an inexpensive home network will run at very high speeds, usually 10 or 100 Mbps. That's 200-2,000 times faster than a 56K dial-up connection! You can even configure your network to perform at twice that speed ("full duplex") if you need to stream audio or video across the network. Internet Service Providers (ISPs) may run their networks at 1000 Mbps (a gigabit of traffic per second).

The Ethernet standard is what allows these machines to talk to one another. Each computer (or printer or other device) on the network has a unique address, or IP Address.

What's an IP address?