Description: What a wireless card does vs. what a router does.

So you bought a new notebook/laptop computer that has a wireless card in it. You're able to get online at the library, your favorite coffee shop, and your friends house, but can't get online at home. Why is that?

Modern notebook computers all come with what is called a wireless card. This is a piece of hardware in the computer that is able to receive a wireless signal that connects to the internet.

A router is a separate device that connects to the modem (often supplied by the Internet Service Provider, or ISP) and turns the wired-only signal of the modem into a wireless signal for the wireless card in the computer to receive.

In short, the router broadcasts a signal like a TV station (with much less range) and the wireless card is like the antenna that receives the signal and interprets it to display on the screen.