Explanation:

Data communication refers to the transmission of the digital data between two or more computers The physical connection between networked computing devices is established using either cable media or wireless media. The best-known computer network is the Internet.The medium is also called channel. In the communication process, a medium is a channel or system of communication—the means by which information (the message) is transmitted between a speaker or writer (the sender) and an audience (the receiver). The plural form is media, and it's also known as a channel.
Ex : coaxial cable is a medium and it is used as a channel for communication.