In telecommunications, transmission is the process of sending and propagating an analogue or digital signal using a wired, optical, or wireless electromagnetic transmission medium.[1][2]
Antenna used for transmission of radio signals
Transmission technologies typically refer to physical layer protocol duties such as modulation, demodulation, line coding, equalization, error control, bit synchronization and multiplexing, but it may also involve higher-layer protocol duties, for example, digitizing an analogue signal, and data compression.
Transmission of a digital message, or of a digitized analogue signal, is known as data transmission.
Examples of transmission are the sending of signals with limited duration, for example, a block or packet of data, a phone call, or an email.