|
A digital system is one that uses discrete values (often electrical voltages), representing numbers or non-numeric symbols such as letters or icons, for input, processing, transmission, storage, or display, rather than a continuous spectrum of values (ie, as in an analog system).
The distinction between "digital" and "analog" can refer to method of input, data storage and transfer, or the internal working of a device. The word comes from the same source as the word digit and digitus: the Latin word for finger (counting on the fingers) as these are used for discrete counting.
The word digital is most commonly used in computing and electronics, especially where real-world information is converted to binary numeric form as in digital audio and digital photography. Such data-carrying signals carry one of two electronic or optical pulses, logic 1 (pulse present) or 0 (pulse absent).
Digital telephone services use VoIP technology to route ordinary telephone calls over a packet-switched digital network.
Most of these services allow customers to continue using a traditional touch-tone telephone, in conjunction with a special IP adapter.
Several major cable providers in Canada and the United States have launched digital phone offerings, allowing customers to route calls over cable broadband networks.
Historical digital systems
|
