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aurora Sonata Hand Held ISDN Tester—User Guide
A4-2 427869
Glossary & Abbreviations
A-law
Companding technique for Pulse Code Modulation, used
in Europe.
Address
A sequence of bits or characters which uniquely identify a
user, element or application. For example, the number
entered by a caller to identify the called party.
ANSI
American National Standards Institute. The national co-
ordinating organisation for voluntary standards in the US.
ASCII
American Standard Code for Information Interchange.
The US version of the ISO 7-bit data code. Usually
transmitted in 8-bit characters, the additional bit being an
odd or even parity bit.
Asynchronous
The description used for a communications channel
capable of transmitting data but not timing.
AT&T
A custom ISDN protocol used by AT&T.
aurora
Expert
A protocol analysis package that can be used in
conjunction with the aurora family of ISDN testers.
B channel
Bearer channel. ISDN utilises multiplexed channels that
are transmitted over the same physical medium. The B
channels typically carry the user's voice/data/video.
Basic Rate
A type of ISDN circuit typically used for subscriber
circuits. It consists of two B channels and one D channel,
giving 144kbps of bi-directional user communications.
Baud Rate
The number of line signal transitions per second. In a
simple system where each bit is represented by a single
level it is the same as the number of bits per second.
BER
Bit Error Ratio/Rate. A measure of transmission quality:
the number of errored bits divided by the total number of
bits transmitted in a specific interval.