Data communication refers to the exchange of data between a source and receiver via transmission media like wires or cables. It is classified as local if devices are near each other or long distance otherwise. The basic elements of communication are messages, senders, receivers, and an encoding/decoding process to transmit messages through a medium. There are three main types of communication modes - simplex allows one-way transmission, half-duplex allows bidirectional transmission but not simultaneously, and full-duplex allows simultaneous bidirectional transmission. Wireless broadband uses radio waves to provide high-speed internet connectivity over a wide area.