Atto (10^-18). See metric system.

Application and Service Capabilities

Access Border Gateway Function..

In a start-stop teletypewriter system, the significant condition of the signal element that immediately precedes a character signal or block signal and prepares the receiving equipment for the reception of the code elements.

Analog-to-digital. See analog transmission.

Assisted Global Navigation Satellite System (A-GNSS)

Assisted Global Positioning System

See a-law algorithm.

A standard compression algorithm, used in digital communications systems of the European digital hierarchy, to optimize, i.e., modify, the dynamic range of an analog signal for digitizing. Note: The wide dynamic range of speech does not lend itself well to efficient linear digital encoding. A-law encoding effectively reduces the dynamic range of the signal, thereby increasing the coding efficiency and resulting in a signal-to-distortion ratio that is superior to that obtained by linear encoding for a given number of bits.

1. Audio and Video; 2. Audio/Video