results in the disappearance of a picture to black or, in the case of fade in, the gradual introduction of light to an all-black image. fast packet multiplexing The combination of TDM, packet and computer intelligence to allow multiple digital signals to share a high-speed network. Fast packet multiplexing assumes a clean network and, therefore, does not buffer information, but rather moves it along, and assumes it will arrive with little or no degradation. The two most common forms of fast packet multiplexing are cell relay and frame relay. Federal Communications Commission, a US regulatory body established by Congress in 1934. Fiber Distributed Data Interface. An ANSI standard for a 100 Mbps token-ring-based fiber-optic LAN. It uses a counter-rotating token ring topology and is compatible with the physical layer of the OSI model. FDDIII Emerging ANSI standard that incorporates both circuit and packet switching over fiber optics at 100 Mbps. Not compatible with the original FDDI standard. Frequency Division Multiplexing. A method of transmitting multiple analog signals on a single carrier by assigning them to separate and unique frequency bands and then transmitting the entire aggregate of all frequency bands as a composite. fiber optics cable A core of fine glass or plastic fibers that has extremely high purity and is surrounded by a cladding of a slightly lower refractive index. Light or infrared pulses that carry coded information signals are injected at one end. They pass through the core using a method of internal reflection or refraction. Attenuation is low; pulses travel as far as 3,500 feet or more before needing regeneration. field A normal television image is comprised of interlaced fields-each field contains one-half of a video frame's Video Communication: the Whole Picture information. Each field carries half the picture lines. In the NTSC video standard 60 fields/30 frames are sent in a second and in the European PAL and SECAM systems 50 fields/25 frames are sent in a second. field interlacing In te