The card goes inside your computer and has the jack on it that you plug to your network or the box (router/modem) that connects you to the internet. The jack looks like a large telephone jack (where you plug your phone to the phone line). The phone plug is RJ-11 and the one for networks is RJ-45. The phone cord has the ability for 6 little wires in the cable and the network cable has 8 little wires in it.
The card takes the signal from the network/internet and changes it to a signal the computer understands and does the opposite when sending information from the computer.
Sometimes the card is made as a part of the motherboard (the main circuit board in the computer that has all the computer hardware components). On desktop personal computers the network card is usually separate and on laptops it is usually built in the motherboard.
Network cards can work with wired networks using a RJ-45 jack and you can also get network cards that work with wireless networks (the signal is transmitted thru the air). On a wireless network card you will not find a network jack but will see an antenna attached to the card.
Many computers and networks today use wireless, although there are plenty of wired networks. The advantage of wireless is you are not limited to just where the wire plugs in to the network. Wired networks work faster and are more secure.
You can purchase network cards at office supply stores, computer stores and large discount stores like Walmart and K-Mart.
Send your questions to Dwight Watt at email@example.com. He teaches at a technical college in northwest Georgia and does consulting work for businesses and individuals. His website is www.dwightwatt.com.