ATT System 25 Reference Manual

AT&T 555-540-200
Issue 1, September 1989
AT&T System 25
Release 3, V 3
Reference Manual 

TO ORDER COPIES OF THIS MANUAL (INCLUDES ADDENDUM)
Call: AT&T Customer Information Center on 1-800-432-6600
In Canada Call 1-800-255-1242
Write: AT&T Customer Information Center
2855 North Franklin Road
P.O. Box 19901
Indianapolis, IN 46219-1385
TO COMMENT ON THIS ADDENDUM
Call: The AT&T Document Development Organization
Hot Line: 1-800-334-0404
In North Carolina Call (919) 727-6681
While reasonable efforts were made to ensure that the information
in this document was complete and accurate at the time of...

FCC NOTIFICATION AND REPAIR INFORMATION
AT&T SYSTEM 25
This telephone equipment is registered with the Federal Communications Commission (FCC) in
accordance with Part 68 of its Rules. In compliance with the Rules, be advised of the following:
MEANS OF CONNECTION
Connection of this telephone equipment to the nationwide telecommunications network shall be
through a standard network interface USOC RJ21X jack. Connection to private line network
channels requires USOC RJ2GX jack for tie lines or USOC RJ21X...

REPAIR INSTRUCTIONS
If you experience trouble with this telephone equipment, contact the AT&T National Service Center
on 1-800-628-8888. The Telephone Company may ask that you disconnect this equipment from the
network until the problem has been corrected or until you are sure that this equipment is not
malfunctioning.
RIGHTS OF THE TELEPHONE COMPANY
If your telephone equipment causes harm to the telephone network, the Telephone Company may
discontinue your service temporarily. If possible, they will...

FCC WARNING STATEMENT
Federal Communications Commission (FCC) Rules require that you be notified of the following:
l This equipment generates, uses, and can radiate radio frequency energy and, if not installed
and used in accordance with the instruction manual, may cause interference to radio
communications.
l It has been tested and found to comply with the limits for a Class A computing device pursuant
to Subpart J of Part 15 of FCC Rules, which are designed to provide reasonable protection
against such...

Common carriers are required by law to collect their tariffed charges. While these charges are
fraudulent charges made by persons with criminal intent, applicable tariffs state that the customer
of record is responsible for payment of all long-distance or other network charges. AT&T cannot
be responsible for such charges and will not make any allowance or give any credit for charges
that result from unauthorized access.
To minimize the risk of unauthorized access to your communications system:
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l
l
l
l...

CONTENTS
CONTENTS
Section 1—Overview
Section 2—Features and Services
Section 3—Functional Description
Section 4—Hardware Description
Section 5—Technical Specifications
Section 6—Environmental Requirements
Section 7—Parts Information
Section 8—Reference Documentation
Section 9—Glossary
Section 10—Index 

OVERVIEW
Introduction
Organization
System 25 Description
Call Handling Capabilities
Safety
Business Communications Needs
Incoming Business Communications
Outgoing Business Communications
Internal Call Movement
Data Communications
Growth & Rearrangement
Conclusions
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Figures
Figure 1-1.System 25 Block Diagram                                                                                     1-2
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OVERVIEW
OVERVIEW
Introduction
This reference manual provides general technical information on AT&T System 25 (System
25). It includes a description of the system, its hardware and software, features and
services, environmental requirements, and technical specifications. This manual is intended
to serve as an overall technical reference for System 25.
This manual is released specifically to cover Release 3 (R3) of System 25. It does not
contain information that applies only to the earlier releases of...