sion into its original form. Decryption applies a special decoding algorithm (key) to the encrypted exchange; any party without access to the proper key required for decryption can not receive the transmission in an intelligible form. dedicated access A leased, private connection between a customer's equipment and a telephone company location, most often that of an IXC. dedicated leased line A transmission circuit leased by one customer for exclusive use around the clock. See also private line. delay The time required for a signal to pass between a sender and a receiver; alternately the time required for a signal to pass through a device or conductor. demultiplex The process of separating two or more signals previously combined for transmission over a shared channel. Multiplexing merges multiple channels onto Video Communication: the Whole Picture one channel prior to transmission; de-multiplexing separates them again at an appropriate network node. Often shortened to DeMUX. depth of field The range of distances from the camera in which objects around a focal point (the distance from the surface of a lens or mirror to its subject)) will be in focus. Use of a smaller lens aperture increases depth of field. Data encryption standard developed by the National Bureau of Standards and specified in the FIPS Publication 46, published in January 1977. Generally replaced by AES. desktop A term used to refer to a desktop computer or workstation used by an individual user. Dense wavelength division Dense WDM transmits up to 32 OC-48 (2.5Gbps) multiplexing signals over a single fiber, and offers the potential to transmit trillions of bits per second over one fiber. dial-up The ability to arrange a switched connection, whether analog or digital, by entering a terminating address such as a telephone number, in order that the call can be routed by the network. Differs from point-to-point services that can be used only to communicate between two locations. digital Information that is represented using codes that consist of zeros 