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GLOSSARY
Bit Error Rate (BER)
Blue Alarm Signal
BOC
Bps
Byte
Card
Channel
Channel Service Unit
(CSU)
Character
Clock
Common Carrier
Contention
Control Characters
Controlled Slip Event
B-2
The percentage of received bits that are in error, relative to a specific amount of
bits received; usually expressed as a number referenced to a power of 10; e.g., 1 in
10 5 .
See Alarm Indication Signal.
Bell operating company; one of 22 local telephone companies spun off from
as a result of divestiture.
Bits per second; basic unit of measure for serial data transmission capacity; also
kbps (kilobits), for thousands of bits per second; Mbps (megabits), for millions of
bits per second; Gbps (gigabits), for billions of bits per second; Tbps (terabits), for
trillions of bits per second.
Generally an 8-bit quantity of information, used mainly in referring to parallel
data transfer, memory capacity, and data storage; also generally referred to in
data communications as an octet or character.
A card is an assembly of components that can be tested, removed, and replaced as
a unit. A card usually refers to a single unit without piggybacks connected to it.
Also called pc board.
Part of a circuit path through several entities in a communication
channel runs between two nodes.
A component of customer premises equipment (CPE) used to terminate a digital
circuit, such as DDS or T1, at the customer site; performs certain line-condition-
ing features, ensures network compliance per FCC rules, and responds to loop-
back commands from central office; also, ensures proper ones density in trans-
mitted bit stream and performs bipolar violation correction.
Standard bit presentation of a symbol, letter, number, or punctuation mark.
An oscillator-generated signal that provides a timing reference for a transmis-
sion link; used to control the timing of functions as sample interval,
rate, and duration of signal elements; an "enclosed" digital network typically
has only one "master" clock.
In the United States, any supplier of transmission facilities or services to the gen-
eral public that is authorized to provide such facilities or services by the appropri-
ate regulatory authority and bound to adhere to the applicable operating rules, such
as making services available at a common price and on a nondiscriminatory ba-
sis.
Competition among customer channels, on a first in/first out basis, for the right to
use a transmission channel, whether a PBX circuit, a computer port, or a time
slot, within a multiplexed digital facility.
Any transmitted characters, not message or user data, used to control or facilitate
data transmission between data terminal equipment (DTE); includes extra char-
acters associated with addressing, polling,
framing, synchronization, and error checking.
A controlled slip event is the occurrence of a replication or deletion of one DS1
frame by the receiving equipment, and is counted as one event. A controlled slip
event occurs when the difference in the timing between the synchronous
equipment and the received signal is of such magnitude that it exhausts the buffer
capability of the equipment.
message
delimiting
and
AT&T
system.
A
signaling
blocking,
receiving
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