Data transfer or data transmission refers to the transfer of data, usually a digital bit stream, over a medium such as copper wire, optical fibre, storage medium and wireless channel. The data are transformed into signals which are analog or electromagnetic in nature, such as electric, radio wave, microwave, infrared, or sound signal. Analog data transfer relies on continuous varying analog signal transfer while the digital one makes use of discrete messages during transfer.
Data transfer or file transfer is an act of transmitting data over networks like the internet in which various protocols are used. Data transfer over networks can be either an upload or download depending on the user’s perspective.
For streaming over the Internet, video and audio files are transferred from a host computer called a server to a client computer. The server can be located anywhere in the world. And the client can be anywhere, generally using any device (e.g. laptop, smartphone, tablet). The protocols used to transfer the streaming data, the “data transfer” in this case, varies depending on the settings of the server and the client.
Typical protocols used for data transfers on the Internet are Real Time Streaming Protocol (RTSP), Universal Datagram Protocol (UDP), Real-Time Transport Protocol (RTP), Real Time Messaging Protocol (RTMP), HTTP Live Streaming (HLS), and the most basic protocol of Transmission Control Protocol (TCP).
For many years Flash was the primary format for streaming video. It used the RTMP protocol. But over time Flash has become less popular and other protocols such as HLS have gained in popularity. HLS is Apple’s primary or preferred format.
Data transfer is also a term used in computer buses for communication with external equipment through parallel and serial ports such as Universal Serial Bus (USB) and Firewire. Storage media such as external hard drives and memory cards also make use of data transfer. Data transfer is also occurring in computer network devices such as modems, LAN adapters, hubs, repeaters, etc.