ATT System 25 Installation And Maintenance Manual

							GLOSSARY
FacilityBy technical type these include loop-start, ground-start, DID, data,
and automatic ringdown trunks. These facilities may be accessed by
their facility access codes (FACS).
Restriction Level (FRL)
A restriction parameter associated with the Automatic Route
Selection (ARS) feature.Determines whether a particular station can
access a particular trunk.
Fast Busy Tone
Feature
Feature
Foreign
Foreign
ForeignSee Reorder Tone.
A specifically defined function or service provided by the system.
Button
A labeled
designatingbutton on a voice terminal or attendant console
a specific feature.
Exchange (FX)
A central office
public telephone
Exchange Trunkother than the one providing local access to the
network.
A telecommunications channel that directly connects the system to a
central office other than its local central office.
Numbering Plan Area (FNPA) Code
An area code other than the local area code. The FNPA code must
be dialed to call outside the local numbering plan area.
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							GLOSSARY
Ground-Start Trunk
On outgoing calls, System 25 transmits a request for service to the
distant switching system by grounding the trunk ring lead. When the
distant system is ready to receive the digits of the called number,
that system grounds the trunk tip lead. When System 25 detects this
ground, it removes the ground from the ring lead and the trunk is
ready for service.
Home Numbering Plan Area (HNPA) Code
The local area code. Does not have to be dialed to place calls to
numbers within the local numbering plan area.
Immediate-Start Tie Trunk
After establishing a connection with the distant switching system for
an outgoing call, the system waits a nominal 65 milliseconds before
sending the digits of the called number. This allows time for the
distant system to prepare to receive the digits. Similarly, on an
incoming call, the system has 65 milliseconds to prepare to receive
the digits.
Intercept Tone
On System 25, this tone is the same as Reorder Tone. Indicates a
dialing error or denial of the service requested.
Interface
Internal
A common boundary between two systems or pieces of equipment.
Call
A connection between two stations within the system. Sometimes
called an inside or intercom call.
l-Use Lamp
A red lamp on a multiline voice terminal that lights
appearance will be selected when the handset is
appearance is active when a user is off-hook.to show which call
lifted or which call
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							Loop-Start Trunk
Modem
ModemSimplest type of central office (CO) trunk. Calls are originated by
providing a dc path between the tip and ring leads. The CO detects
the loop current thus drawn and returns dial tone. Incoming calls are
signaled by the CO placing an ac ringing voltage between the tip and
ring leads. (The port circuit pack detects this signal.)
A device that modulates and demodulates signals transmitted over a
communications path. Used to connect Data Terminal Equipment to
the system’s analog ports. The system (optionally) provides a 212A
compatible conversion resource.
Pooling
Provides shared-use conversion resources that eliminate the need
for dedicated modems.
Multiline Voice Terminal
A terminal equipped with several call appearance buttons for the
same extension number. Allows
call at the same time.
Multiplexed
The simultaneous transmission
common transmission medium.
Networkthe user to handle more than one
of two or more signals over a
An arrangement of inter- and/or intra-location circuits designed to
perform specific functions.
Network Interface
Provided by the telephone company in three forms:
(1) RJ21X for trunk facilities other than tie trunks.
(2) RJ2GX for tie trunk facilities.
(3) RJ48X or RJ48G for DS1 Tie Trunk facilities.
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							GLOSSARY
Number Plan Area (NPA)
The area code.
Off-Premises Station (OPS)
An arrangement provided by the local telephone company permitting
remote terminal equipment to operate as though it were directly
connected to the system.This tariffed service can be provided only
for FCC-registered single-line voice terminals.
Out-of-Building Station
Terminal equipment directly connected to the system, but not located
in the same buildingas 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 the RS-232C channels on the
CPU/Memory circuit pack. Examples are the System Administration
Terminal (SAT), SMDR Output device such as a Printer or a Call
Accounting System, Digital Tape Unit (DTU), and Customer Service
Unit (CSU).
Personal Dial Code (PDC)
Voice terminal extension number.
Each system user is assigned a PDC and is allowed to “log in” the
PDC at any voice terminal in the system. The PDC may be a 1-, 2-,
3-, or 4-digit number. There are two types of PDCs:
l The PDCs assigned to voice terminals—One is associated
with each voice terminal in the system.
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							GLOSSARY
l Floating—Assigned to visitors who will be moving about the
premises.Floating PDCs may be associated with the
attendant position or may be “logged in” by the user at any
voice terminal. Calls to the floating PDC will ring at the
terminal where “logged in. ”
Pickup Group
A group of individuals who can answer any incoming call within the
group by dialing a code.
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
needs of a
used exclusively for handling the
particular customer.
Private Network Office Code (RNX)telecommunications
The first three digits of a 7-digit private network number. These
codes are numbered 220 through 999, excluding any codes that have
a 0 or 1 as the second digit.
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							Protocol
A set of conventions or rules governing the format and timing of
message exchanges to
errors.
Public Network
The network that can be
or long-distance calling.
Queuecontrol data movement and correction of
openly accessed by all customers for local
An ordered sequence of tasks to be processed.
Queuing
.The process of holding calls in order of their arrival to await
connection to an attendant, to a DGC group, or to an outgoing trunk.
Calls are automatically connected in first-in, first-out sequence.
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
arrangement primarilyforinformation
retrieval
applications.
Recall Dial Tone
Three short bursts of tone (confirmation tone) followed by steady dial
tone; indicates that the system has completed some action (such as
holding a call) and is ready to accept dialing.
Redirection Criteria
The information administered for each voice terminal that determines
when an incoming call is redirected to coverage.
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							GLOSSARY
Reorder Tone
Atone repeated 120 times a minute; indicates that at least one of the
facilities, such as a trunk or a digit transmitter, required for the call is
not available. Also called Fast Busy Tone.
Single-Line Voice Terminals
Single-line voice terminals served by a Tip Ring Line or Analog Line
circuit pack (2500 series and 7101 A voice terminals or industry
standard Dual-Tone  Multifrequency equivalent).
Software
A set of computer programs that accomplishes one or more tasks.
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 (Personal 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 assigned DDCs
(Data Dial Codes).
Station Interconnect Panel (SIP)
The station cross-connect field.
Station Message Detail Recording (SMDR)
Data output by System 25 that provides a record of each incoming
and outgoing call.
Status LED (Lamp)
A green LED or lamp that shows the status of a call appearance or a
feature button by the state of the lamp (lighted, flashing, fluttering,
broken flutter, or dark).
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							GLOSSARY
Switch
The software-controlled communications processor complex that
interprets dialing pulses/tones/keyboard characters and makes the
proper interconnections both within the system and outside the
system. The switch itself consists of a digital computer, software,
storage device (memory), and associated circuit packs
hardware necessary to perform the actual connections.
Switchhook
and special
The button(s) on a voice terminal located under the receiver. A user
typically goes “off-hook” to place or answer a call by picking up the
receiver and goes “on-hook” (hangs up) to end a call.
The RS-232C DTE peripheral equipment used to enter and change
system translations.
Synchronization
System
SystemCoordinated timing whereby all switches,
multiplexer operate from the same stable
process assures that the transmit and the
achieve proper bit alignment.
Administratorchannel banks, and
clock reference. The
distant receive node
A person responsible for specifying and administering features and
services for the system.
Restore
A process that allows stored data to be written from a tape into the
system memory (normally after a cold start).
T1
The T1 carrier system is a high speed, time division multiplexed,
digital transmission facility capable of transmitting voice and data at
1.544 Mbps. In System 25, T1 can replace up to 24 analog trunks,
offering improved quality, cost savings, and enhanced features.
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							GLOSSARY
Terminal Equipment
Equipment used to change information (sound, keystrokes) into an
electrical signal compatible with System 25’s port circuits. (Voice
and data terminals are the two primary types.)
Tie Trunk
A telecommunications channel that directly connects two private
switching systems.
Time-Division Multiplex Bus
A special bus that is time-shared by preallocating short time slots to
each transmitter on a regular basis. In a PBX, all port circuits are
connected to the time-division multiplex bus, permitting any port to
send a signal to any other port.
.
Tone Ringer
A device with a speaker, used in electronic voice terminals to alert
the user.
Translations
Specific information
customized for the
through the SAT.
Trunkassigned to a terminal or to the system and
user. Translations are entered and changed
A telecommunications channel between two switching systems.
Trunk Access Equipment (TAE)
The cross-connect field for central office (CO)/network facilities.
G-16 
						

							GLOSSARY
Trunk Group
Telecommunications channels assigned as a group for certain
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 of 48-
volt power. One unit load equals 44 mA.
Voice Terminal
A single-line or multiline voice instrument (that is, telephone). See
Terminal Equipment.
Wide Area Telecommunications Service (WATS)
A service that allows calls to a certain area or areas for a flat-rate
charge based on expected usage.
Wink-Start Tie Trunk
After establishing a connection with a distant switching system for
an outgoing call, the system waits for a momentary signal (wink)
before sending the digits of the called number. Similarly, on an
incoming call, the system sends the wink signal when ready to
receive digits.
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.
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