ADTRAN 1200270L1, Manual

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Appendix F. Glossary
F-2 DSU III ARdc User Manual 61200270L1-20
BERT
Bit error rate test. A known pattern of bits is transmitted and the
errors received are counted to figure the bit error rate. The idea is to
measure the quality of data transmission. The bit error rate is the
ratio of received bits that are in error, relative to the number of bits
received (usually expressed in a power of 10).
bisync
Bisynchronous transmission. A half-duplex, character-oriented, syn-
chronous data communications transmission method originated by
IBM in 1964.
carrier detect
CD. A signal generated by a DCE (a modem or DSU/CSU). CD
informs the DTE device if the DCE is receiving a carrier signal from
the line. If the CD light is on, the device is speaking to another
device.
channel service unit
CSU. A DCE device used to connect a digital phone line (T1 or
Switched 56 line) coming in from the phone company to either a mul-
tiplexer, channel bank, or directly to another device producing a digi-
tal signal (for example, a digital PBX, a PC, or data communications
device). A CSU performs certain line-conditioning and equalization
functions, and responds to loopback commands sent from the central
office. A CSU regenerates digital signals, monitors them for prob-
lems, and provides a way of testing the digital circuit.
clocking
An oscillator-generated signal that provides a timing reference for a
transmission link. A clock provides signals used in a transmission
system to control the timing of certain functions. The clock has two
functions: (1) to generate periodic signals for synchronization, and
(2) to provide a time base.
controller card
The card installed in slot 1 of an ADTRAN SMART 16 shelf, used to
connect a VT 100 terminal or DATAMATE for configuring SMART 16
DSU/CSU products.