Data transmission / Data transfer Data transfer is the process by which data or information from one source travels to a destination via a medium. Data transfer can either be a point to point or multipoint. The channel is the medium used in transfer including copper wires, optical fibers, wireless communication channels, modems, etc. Data is usually represented as an electromagnetic signal, usually an electrical voltage, radio wave, microwave or infrared signals. The rate of data transfer defines the speed at which one unit of data is transferred per second from one source to a destination. The speed of data transfer is usually measured in bits per second (for digital data) and is based on the medium. Data transfer speed is measured in various units including those of the device and the standard that is used. There is a particular standard even for Universal Serial Bus controllers (USBs) where the device determines the speed of the data transfer and is designed for that