Instruction manual

OVERVIEW
Growth & Rearrangement
Historical data indicates that clients in the System 25 station range have a need for
communications systems capable of significant growth and rearrangement. Clients need
flexibility over the life of the system to easily add capacity, move stations, modify cost control
options, etc. The architecture of System 25 was implemented with the objective to meet this
need.
● Advanced Administration (optional) is an easy-to-use, menu driven personal computer
software package for configuring the rich set of system options. Versions of this software
are available for both MS-DOS and UNIX personal computers.
● Uniform Wiring Plan (four-pair) allows a building to be prewired for the rich set of AT&T
Small Business PBX service offerings.
This modular wiring plan supports client
reconfiguration of an office with variations in station type (Analog, MET, MERLIN
Communications
System,
futures) and
data configurations (LAN, asynchronous,
synchronous). It supports simultaneous voice and data from standard 4-pair modular jacks.
● System 25/75/85 and DEFINITY™ Communications System, Generic 1 and Generic 2
Standard Architecture supports efficient growth with modular cabinets, universal carrier
slots, nonblocking network, and uniform wiring plan. Every circuit slot in the system can be
used for trunk cards or voice/data station cards. All these attributes allow the client to add
future capability without breakage and re-engineering of existing equipment. Thus, the
client is able to minimize initial investment while not restricting future growth.
Over time, the type of tools and facilities that a business utilizes changes. It is important that
a PBX provide support for the full set of telephone company network options over its
installed life, even when only a subset is initially used. Trunks link two switching systems,
such as System 25 and the local Central Office or System 25 and another PBX. System 25
supports five different telephone company trunk interfaces to provide desired connectivity at
minimum expense. Thus the opportunity exists to select the best trunk types, depending on
tariffs and customer needs. For example:
● Loop Start (LS) trunks for public network access at minimum tariff. These trunks
handle outgoing and incoming attendant calls, incoming DGC calls, outgoing pooled
facility calls, and personal line calls.
● Ground Start (GS) trunks for public network access. These trunks handle the same
type of calls as LS trunks. They provide protection against call reorigination without
toll restriction, more reliable automatic route selection, virtual facilities, SMDR, and
CAS. Simultaneous incoming and outgoing call seizure of the same trunk under
heavy traffic conditions is essentially eliminated with ground start trunks. GS trunks
should usually be selected in preference to LS trunks unless tariff considerations are
overriding. Note, however, that Centrex Service requires LS trunks.
● Direct Inward Dialing (DID) trunks for dialing a station directly from outside (attendant
assistance not required). Outside dial access to stations, trunks (optional), and
answering groups (Direct Group calling) is provided.
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