Data communication networks are systems that allow computers and devices to exchange information. They use various technologies, such as cables, wireless signals, and protocols, to transmit data over distances. These networks can be local, like a home Wi-Fi network, or wide-ranging, like the Internet. These networks consist of hardware components, including routers, switches, and servers, which help manage and direct data traffic. They enable different devices, such as smartphones, laptops, and printers, to communicate effectively, facilitating activities like browsing the web, sending emails, and sharing files.