Analog describes a device or system that represents changing values as continuously variable physical quantities. A typical analog device is a clock in which the hands move continuously around the face. Such a clock is capable of indicating every possible time of day. In contrast, a digital clock is capable of representing only a finite number of times (every tenth of a second, for example). In general, humans experience the world analogically. Vision, for example, …showed first 75 words of 774 total…

…showed last 75 words of 774 total…network service. As a consequence of this shift, there is likely to be a far richer set of voice services available, raising the prospect of IP-based telephony offering a richer and more powerful suite of services while the traditional PSTN remains in place. At the same time, considerable attention is being paid to the development of IP-PSTN interoperability capabilities in the form of gateways between IP and circuit-switching technologies, enabling the creation of hybrid services.