Animated Telecom Dictionary
Use this dictionary for an understanding of the most recent telecom terms, definitions and acronyms, look at detailed animations, learn to search telecom databases, and more.
TABLE OF CONTENTS Animated Telecom Dictionary
A: A & B Bits Azimuth
A & B Bits
Bits that are designated on a digital transmission line (such as a T1 line) to convey signaling information. These bits generally indicate if loop current is present or if the flash service request (momentary on-hook) has been requested.
A & B Leads
Additional leads that are used in addition to a two-wire E&M interface to provide additional control information. A & B leads are used to connect certain types of private branch exchanges (PBXs).
A & B Signaling
A process of transferring signaling information on a digital communication line that involves the stealing of bits from the digital transmission line (called the A & B bits). This is a type of in-band signaling as it steals some of the channel bandwidth for use as signaling messages. When it is used in T1 transmission line, 1 bit of user data from each of the 24 sub-channels in every sixth frame is stolen (discarded) and replaced with signaling control information. The use of A+B signaling reduces the T1 bandwidth from 1.544Mbps to 1.536 Mbps.
A B Bits
See ABCD Bits
A B C D bits
In associated bit signaling used with 2.048 Mb/s digital multiplexing, four bits in the associated signaling channel are used to convey supervisory or other control information. These bits are designated with the letters A, B, C, and D. In robbed bit signaling used with 1.544 Mb/s digital multiplexing, the robbed bits used in the 6th and 12th frames are designated the A...
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