Network and interface cards extend desktop computers and laptops to various inputs and outputs. They are prefabricated components that are usually plugged into the appropriate receptacles or in the corresponding interface on the desktop computer or laptop. Installation effort is minimal. Interface cards, inserted into a free PCI or PCI Express slot on the motherboard, can expand your printer, monitor or fast USB ports. Network cards can be installed just as easily and have an Ethernet input for connecting an RJ45 cable. This way, older PCs can be upgraded and connected to the Internet.