An SIT (special information tone) classification for call attempts that fail to find an available Local Service Provider outgoing trunk. [T1.207-1998]

[An] Area, room, or space that, when staffed, must be occupied by two or more appropriately cleared individuals who remain within sight of each other. [INFOSEC-99]

Network Operations Center

Acronym for network outward dialing.

The principal clock or alternate clock located at a particular node that provides the timing reference for all major functions at that node.

Synonym node.

1. In network topology, a terminal of any branch of a network or an interconnection common to two or more branches of a network. Synonyms junction point, nodal point.
2. In a switched network, one of the switches forming the network backbone.
Note: A node may also include patching and control facilities.
3. A technical control facility (TCF).
4. A… (Read More →)

1. An undesired disturbance within the frequency band of interest; the summation of unwanted or disturbing energy introduced into a communications system from man-made and natural sources.
2. A disturbance that affects a signal and that may distort the information carried by the signal.
3. Random variations of one or more characteristics of any entity such as voltage, current, or… (Read More →)

1. Interfering and unwanted electrical currents in a device or system.
2. In optical communications, the rms component of the optical detector output electrical current with no incoming signal present.

At a given data-signaling rate or modulation frequency, operating wavelength, and effective noise bandwidth, the radiant power that produces a signal-to-noise ratio of unity at the output of a given optical detector.
Note 1: Some manufacturers and authors define NEP as the minimum detectable power per square root bandwidth. When defined this way, NEP has the units of watts per… (Read More →)