ATT System 25 Maintenance Manual

GLOSSARY
Out-Of-Building Station
Terminal Equipment directly connected to the system, but not
located in the same building as the common equipment. Special
arrangements are made to protect the system and its users from
lightning, power line crosses, etc.Only single-line and 7300H series
voice terminals may be so connected. (MET sets cannot be
connected as Out-of-Building stations.)
Paging Trunk
A telecommunications channel used to access a paging system.
Peripheral Equipment
Equipment connected to one of...

GLOSSARY
Port
An interface circuit between System 25 and associated trunks and
terminals. Specifically:
l Terminal port (station port)
l Facility port (trunk port)
l Auxiliary equipment port.
Private Branch Exchange
A switching system that provides switched communications access
among its terminals and facilities (for example, System 25).
Private Network
A network used exclusively for handling the telecommunications
needs of a particular customer.
Private Network Office Code (RNX)
The first three digits...

GLOSSARY
Random Access Memory (RAM)
A storage arrangement whereby information can be retrieved at a
speed independent of the location of the stored information.
Read Only Memory (ROM)
A storage
arrangementprimarily for information retrieval
applications.
Recall Dial Tone
Three short bursts of tone (confirmation tone) followed by steady dial
tone; indicates the system has completed some action (such as
holding a call) and is ready to accept dialing.
Redirection Criteria
The information administered for...

GLOSSARY
Station
A place where terminal equipment is located or sometimes the
terminal equipment itself. Each voice terminal (station) is assigned a
station (extension) number.Users of the terminal are sometimes
referred to as station users. Reference to the extension number is
sometimes in the form PDC (PersonaI Dial Code) rather than station
number. PDCs may be “logged in” at other stations. In most
circumstances,PDCs and station numbers may be used
interchangeably.Analogously, data stations are...

GLOSSARY
System Administration Terminal (SAT)
RS-232C DTE peripheral equipment used to enter and change
system translations.
System Administrator
A person responsible for specifying and administering features and
services for the system.
System Restore
A process that allows stored data to be written from a tape into the
system memory (normally after a cold start).
Terminal Equipment
Equipment used to change information (sound, keystrokes) into an
electrical signal compatible with System 25’s port...

GLOSSARY
Trunk
A telecommunications channel between two switching systems.
Trunk Access Equipment (TAE)
The cross-connect field for central office (CO)/network facilities.
Trunk Group
Telecommunications channels assigned as a group for certain
functions.
Trunk Port
The hardware (circuit pack) providing an interface between the
system and central office (CO)/network trunks.
Unit Load
A measurement used to evaluate a System 25 cabinet’s power load
capacity. Each System 25 cabinet can handle 80 unit loads...

GLOSSARY
Write Operation
The process of putting information onto a storage medium such as
magnetic tape.
800 Service
A service that allows incoming calls from a certain area or areas to
an assigned number for a flat-rate charge based on usage.
12-17 

INDEX
A
Abbreviations 11-1
Acronyms 11-1
Address Leads
Circuit Pack 3-28
Administration Manual 10-1
Administration Manual, Advanced 10-2
Administrative Software 4-1
Alarm Indicators 2-3
Alarms 2-2
Allocation
Memory 4-2
Analog Line (TN742) 3-41
ATL Line (ZTN79) 3-35
Automatic Maintenance Tests 5-5
Auxiliary Trunk (TN763) 3-49
B
Backplane Trouble 8-18
Bus
TDM 3-16, 4-5
C
Cabinet Trouble 8-18
Call Description 4-7
Call Processor Circuit Pack 3-10, 4-4
Circuit Pack Address Leads 3-28
Circuit Pack LEDs...

INDEX
Data Line
(TN726) 3-37
Troubles 9-11
Dictionary
Error Log 6-5
DID Trunk (TN753) 3-43
Digital Switch 3-3
Digital Tape Unit 3-8
Operation 7-1
Documentation 10-1
DTU 3-8
Operation 7-1
Troubles 9-1
DFailures
Total 5-3
Fan Assembly Trouble 8-17
Frontplane Ribbon Connector Trouble -
8-12
G
General Maintenance Information 2-1
Glossary 12-1
Ground Start Trunk (ZTN76) 3-29
H
Hardware
Overview 3-1
E
IEmergency Transfer 2-3
Unit 3-7
Unit Trouble 8-26
Equipment
DTU 3-8
ETU 3-7
Terminal 3-7
Test 1-3
Trunk...

INDEX
Maintenance Objects 2-1
Maintenance Software 4-2
Maintenance Strategy 5-1
Maintenance Tests 2-5
Automatic 5-5
Memory Allocation 4-2
Memory Bus 3-10
Memory Circuit Pack 3-14
Memory Circuit Packs 4-4
MET Line (TN735) 3-39
Multiple Troubles 9-12
N
New Capabilities Manual 10-3
NPEs (Network Processing Element) -
3-28
O
Overheating Trouble 8-18
P
Panel
617A 3-3
Partitioning
Software 4-3
Pin Assignments
Connector 8-24
Planning Manual 10-3
Pooled Modem (TN758) 3-56
Port Circuit Options
For Stations 9-9...