ADTRAN ATLAS 800 Series Module QUAD E1, User Manual, Page: 172 / 190

Appendix E. Glossary
E-2 ATLAS 800 User Manual 61200180L1-1
byte
Eight bits of information composed of zeros or ones, one of which may include a parity bit.
BRI
Basic Rate ISDN. An ISDN service that offers two bearer (B) channels. One channel (64 kbps) is used
for data transfer and as a data-link. The second channel (16 kbps) is used for signaling and control
information.
clocking
An oscillator-generated signal that provides a timing reference for a transmission link. A clock pro-
vides 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.
CPE
Customer premise equipment. All telecommunications terminal equipment located on the customer
premises, including telephone sets, private branch exchanges (PBXs), data terminals, and customer-
owned coin-operated telephones.
CSU
channel service unit. A device that functions similarly to a modem except that the CSU works with
digital signals rather than analog signaling.
CS
See CTS.
CTS
Clear to send. A signal on the DTE interface indicating that the DCE is clear to send data.
DACS
Digital Access Cross-Connect System. A system, such as the ATLAS 800, that assigns and redistributes
(grooms) any DS0 on any T1 circuit to any other DS0 on any other T1 circuit in the system.
DCE
Data communications equipment. The part of a computer or data terminal that connects to a commu-
nications channel or network.
D channel
delta channel. Controls the operation of the ISDN connection.
dedicated bandwidth
Bandwidth which has been set aside (dedicated) for a specific number.
Dial plan
The numbering plan for ATLAS ports (user and network) handling switched connections. Individual
dial plans contain phone number and features associated with DTMF dialing, PRI and BRI.
Digital Access Cross-Connect System
See DACS.
DNIS
Dialed Number Identification Service. Service provided by a telephone company that allows the caller
to see what number has been dialed.