Local area networks (LANs) allow devices in close proximity like PCs, printers, and other equipment to share resources and communicate. Key elements of a LAN include network cards that connect devices to the network, switches that facilitate faster communication between connected devices, and routers that join multiple networks like a LAN to a wide-area network like the Internet. TCP/IP is the basic communication protocol that allows different operating systems and networks to understand each other using standards like IP addresses to reliably locate devices.