ADTRAN ISU 512e Manual page 144

Glossary
bridging
The technique whereby additional stations may be served from a
two-point facility by extending the facility from a bridge at one of
the facility's terminating points.
CCITT
Consultative Committee on International Telephony and Telegra-
phy. A body of the International Telegraph Union (ITU) which
prepares recommendations, commonly referred to as internation-
al standards, to resolve technical telegraph and telephone prob-
lems.
central office (CO)
In telephony, the phone company switching facility or center, usu-
ally a Class 5 end office, at which subscriber's local loops termi-
nate. Handles a specific geographic area, identified by the first
three digits of the local telephone number. Usually the facilities of
the local BOC.
channel bank
Equipment in a telephone central office that performs multiplex-
ing of lower speed digital channels into a higher speed composite
channel. The channel bank also detects and transmits signaling
information for each channel, transmitting framing information
so that time slots allocated to each channel can be identified by the
receiver.
clear channel
A channel in which all the 64 kbps are used for transmission. To
achieve this bit robbing signaling must be eliminated.
CPE
Customer premises equipment. A generic term for communica-
tions terminal gear owned by the customer, residing on customer
premises.
CSMA/CD
Carrier Sense Multiple Access Collision Detect. A channel access
mechanism where devices check the channel for a carrier before
transmitting. If no carrier is sensed for the specified period of
time, the device can transmit. If two devices transmit at once, a
collision occurs and is detected by all colliding devices. This colli-
sion subsequently delays their retransmissions for a random
length of time. CSMA/CD is used by Ethernet and IEEE 802.3.
CSU
Channel service unit. A component of CPE used to terminate a
digital circuit, such as DDS or T1 at the customer site. Performs
Glossary-2 ISU 512e User Manual 61203086L1-1