Table 6-14--Maintenance Equipment--Continued
Connections between other pairs of telephones are
made over the common path in a similar manner, with
The Dimension 2000 PBX is a time-division
each connection using time-division (microseconds)
switching system. It is designed to give up to 2000
instants for switch closure that differs from that of any
lines and 353 trunks. Solid-state technology makes
possible the use of time-division switching and stored
The primary switching system consists of four
program control. The stored program contains a wide
basic cabinets. These are the common control cabinet,
variety of available features. Self-diagnostic mainte-
the module control cabinet, the line cabinet, and the
nance routines reduce the time required to maintain
auxiliary cabinet. The common control cabinet houses
the system. These features and routines are program-
the processors, memories, and control equipment. The
med on the system's memory tape. Features are added
module control cabinet contains the network control
or modified by input to the memory tape and the
circuits, trunk circuits, and line circuits. Additional
necessary hardware to make the feature work.
line circuits are contained in the line and auxiliary
The system has a battery pack for a backup power
supply. It is capable of supplying the system for a
minimum of 2 hours.
The attendant's console is a desktop piece of
equipment from which the attendant handles
assistance calls. Keys are provided for each of the
Time-division switching is the name given to a
control functions. All calls made by the attendant to
new approach whereby calls travel over the same path
trunk lines or station lines are made using touch-tone
but are separated from each other in time.
dialing or the attendant direct station selection and
In this method the caller and the called party's
trunk group selection feature.
telephone is connected to a common path by a transis-
The console is fully electronic. It is equipped with
torized switch that opens and closes synchronously at
light emitting diode indicators, nonlocking push-
a rapid rate, During the brief closures, 1 microsecond
button control keys, audible ring indicator with
out of every 100 microseconds, a series of pulses is
volume control, and touch-tone telephone pad for dial-
transmitted from the sending connection.
up telephone service.
Each pulse represents a portion of an electric wave
from the calling party's telephone. The electric wave
is reconstructed by the means of a filter, placed
The Dimension 2000 PBX circuits are replaceable
between the switch and the called party's telephone,
circuit cards. The circuit card components are not
which converts into a replica of the voice sound
intended to be replaced in the field. The system is
originated by the calling party.