Degradation of a system in such a manner that it continues to operate, but provides a reduced level of service rather than failing completely.

1. The probability of a call's being blocked or delayed more than a specified interval, expressed as a decimal fraction.
Note: Grade of service may be applied to the busy hour or to some other specified period or set of traffic conditions. Grade of service may be viewed independently from the perspective of incoming versus outgoing calls, and is not… (Read More →)

An optical fiber with a core having a refractive index that decreases with increasing radial distance from the fiber axis.
Note: The most common refractive index profile for a graded-index fiber is very nearly parabolic. The parabolic profile results in continual refocusing of the rays in the core, and compensates for multimode distortion.

In the core of an optical fiber, a plot of the variation of refractive index such that the refractive index decreases with increasing radial distance from the fiber axis.

In graphics, especially computer graphics, that which characterizes an area in which a smooth transition between one color and another, or between black and white (i.e., contrast), takes place.

Systems, including but not limited to: (a) PBX and key telephone systems, directly connected to the public switched telephone network on June 1, 1978, that may remain permanently connected thereto without registration unless subsequently modified, and (b) systems that are of the same type as those connected to the public switched telephone network on July 1, 1978, that were added… (Read More →)

Terminal equipment (other than PBX and key telephone systems) and protective circuitry connected to the public switched telephone network before July 1, 1978, that may remain connected thereto for life without registration unless subsequently modified.

1. A measure of the fineness or coarseness of definition and implementation of a System Security policy [CESG].
2. The relative fineness or coarseness by which a mechanism can be adjusted. The phrase "the granularity of a single user" means the access control mechanism can be adjusted to include or exclude any single user [TCSEC].

1. A visual representation of a character, other than a control character.
2. In the ASCII code, a character other than an alphanumeric character, intended to be written, printed, or otherwise displayed in a form that can be read by humans.
Note 1: Graphic characters are contained in rows 2 through 7 of the ASCII code table.
Note 2: The… (Read More →)

A computer environment or program that displays, or facilitates the display of, on-screen options, usually in the form of icons (pictorial symbols) or menus (lists of alphanumeric characters) by means of which users may enter commands.
Note 1: Options are selected by using the appropriate hardware (e.g., mouse, designated keyboard keys, or touchpad) to move a display cursor to, or… (Read More →)