AT&T System 25 User Manual
Page 417
GLOSSARY
Central Office Codes
The first three digits of a 7-digit public network telephone number.
These codes are numbered from 200 through 999 and are
sometimes referred to as NNXS.
Central Office Trunk
A telecommunications channel that provides access from the system
to the public network through the local central office (CO).
C h a n n e l
A communications path for transmitting voice and data.
Class of Service (COS)
Parameters used to define voice terminal, data, and trunk port
capabilities and restrictions.
Common Control Switching Arrangement (CCSA)
A private telecommunications network using dedicated trunks and a
shared switching center for interconnecting company locations.
C o n f i r m a t i o n T o n e
Three short bursts of tone followed by silence; indicates that the
feature has been activated, deactivated, or canceled.
C o n s o l e
C o v e r a g e C a l l
A call that is redirected from the called station to an alternate
answering position.
C o v e r a g e P a t h
The order in which calls are redirected to alternate answering
positions.
G-4