Really stupid question. I know you can get a wireless thingie that lets you extend your regular ethernet without using a wireless router. I just can't google because all I get are results for wifi.→[More:]

My sister has a computer across a big room from the cable modem. She doesn't want to run a cable across the room. Instead of buying a wireless router, she should get an adaptor that plugs into her non-wireless NIC, and on the other end plugs into her cable modem.

What do you call these? Do they work well?

Thanks!