In the modulation of a carrier, one of the values of the signal parameter chosen to represent information.
Note 1: Examples of significant conditions are an electrical current, voltage, or power level; an optical power level; a phase value; or a frequency or wavelength chosen to represent a "0" or a "1"; or a "mark" or a "yyspace. "
Note… (Read More →)

In a representation of a number, a digit that is needed for a given purpose; in particular, a digit that must be kept to preserve a given accuracy or a given precision.

In a signal, any instant at which a significant condition of a signal begins or ends.
Note: Examples of significant instants include the instant at which a signal crosses the baseline or reaches 10% or 90% of its maximum value.

The time interval between two consecutive significant instants.

In digital telephony, a code composed of a reserved binary number that is sent instead of an actual sound sample value from the CODEC when the incoming voice volume is below a certain level (i.e., when there is no sound). Depending on the transmission system used, the silence code is used for two purposes: (a) to allow other (lower priority)… (Read More →)

Any portion of a ringing cycle during which the ringing signal is not being applied. [T1.401-1998]

Synonym skip zone.

Silicon dioxide (SiO2).
Note 1: Silica may occur in crystalline or amorphous form, and occurs naturally in impure forms such as quartz and sand.
Note 2: Silica is the basic material of which the most common communication-grade optical fibers are presently made. [After FAA]

See silica.

A silicon-based PN- or PIN-junction photodiode.
Note 1: Such photodiodes are useful for direct detection of optical wavelengths shorter than approximately 1 m.
Note 2: Because of their greater bandgap, silicon-based photodiodes are quieter than germanium-based photodiodes, but germanium photodiodes must be used for wavelengths longer than approximately 1 m. [FAA]