ECElec4 Midterms

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SUPERVISION

the CO must provide functions that monitor local loop conditions and other services.

Outlets

the set of output circuits are called the _____________

Equated Busy-Hour Call

(EBHC)

crossbar switch

A ___________ connects n inputs to m outputs in a grid, using electronic microswitches (transistors) at each crosspoint

Telecommunication network

A _________________ is a group of systems that establishes a distant call.

Holding Time

Also, the average duration occupancy of one or more paths by calls

1960s

Businesses adapt PBX Systems

physical layer

Circuit switching takes place at he ____________

dual-tone multifrequency

DTMF

1989

First flip-phone released-targeted at wealthy consumers and priced at 3000 $

multiple crosspoints

Each crosspoint in the middle stage can be accessed by ____________ in the first or third stage

2002

First Blackberry with cellphone service released

space-division switching

In ________________, the paths in the circuit are separated from one another spatially.

space division switching

In __________________, a dedicated path is established between the calling and the called subscribers for the entire duration of the call.

reserved

In circuit switching, the resources need to be __________ during the setup phase; the resources remain dedicated for the entire duration of data transfer until the teardown phase.

Local Access Transport Area

LATA

Holding Time

Length of time during which a call engages a traffic path or channel

black and yellow

Many telephone cables into a home or an ofi ce also contain a second twisted pair if a separate telephone line is to be installed. These wires are usually color-coded _____________.

wireless cell phone

Most homes now have a least one ______________ that is the sole telephone connection.

calling rate

Number of calls per unit time

Open Shortest Path First

OSPF

Stored Program Control

SPC

Circuit switching

Switching method used by the physical layer

Traffic Unit

TU

ringer

The ________in most older telephones is an electromechanical bell. A pair of electromagnetic coils is used to operate a small hammer that alternately strikes two small metallic bells.

calling rate

The average number of calls placed during the busy hour

voice communication

The primary purpose of the telephone system is to provide ________________

central switch

When N gets larger, it is economical to use a ____________

hierarchical switching network

When N is very large and the stations are spread over wide geographical area, one or more levels of intermediate switching is more economical. This leads to a ______________, consisting of a network of switches.

tone

When an incoming call is received, a signal from the central office causes the bell or ringer to produce a ___________.

Space switching arrays

___________ are used in older analog as well as modern digital switching exchanges.

Packet switching

_____________ is popular in computer communication networks.

Bus and Ring topology

alternative methods that connect devices in a network but is not enough especially in long distance communication

Public

anyone can connect to the network

trunk lines

connection between COs

central office

connects any two individual telephones.

access system

consists of the access line to the customer and termination equipment at the end office

network

is a set of connected devices

rectangular array of crosspoints

A single-stage space switch consists of a ______________.

Customer Premises Equipment

CPE

space-division switch, time-division switch

Circuit switching today can use either of two technologies:

Agner Krarup Erlang

Erlang is named after _________

Hundred Call-Second per Hour

HCS

Internet Engineering Task Force

IETF

time division switching

In _____________, sampled values of speech signals are transferred at fixed intervals.

setup phase

In circuit switching, the resources need to be reserved during the ___________; the resources remain dedicated for the entire duration of data transfer until the teardown phase.

IGP

Interior Gateway Protocols

Erlang

One ________ is equal to the number of call-seconds divided by 3600, which is equal to a fully loaded (voice) circuit over a one-hour period.

late 1990s

PBX systems begin integrating VoIP

Message Switching

Switching method used by the application layer

Electronic Switching systems

The _____________ are operated with the help of a processor or a computer which control the switching timings.

Step-by-step switching system

The _____________ is also called the Strowger switching system after its inventor A B Strowger.

wired telephone

The _____________ is gradually becoming history.

switching stations

The ______________ provide connection between different subscribers. Such switching systems can be grouped to form a telecommunication network.

Subscriber Lines

The lines that run to the Subscriber premises are called the _______________

earpiece

The receiver, or ___________, is basically a small permanent-magnet speaker.

100 ohms

The resistance of the telephone itself also varies over a relatively wide range. It can be as low as_________________ and as high as 400 ohms, depending upon the circuitry.

Connection setup, Data TrAnsFer, and connection tear down

Three phases of circuit-switched network

circuit switching, packet switching.

Two distinct switching techniques are employed in communication networks:

Broadcast System

___________ is a one-way communication system

Optimal Routing

_____________ is routing calls from their originating point directly to the terminating mobile without passing (through) Home.

circuit-switched network

A _____________ is made of a set of switches connected by physical links, in which each link is divided into n channels.

single-stage space switch

A ______________ consists of a rectangular array of crosspoints.

call-minute

A ______________ is equivalent to 1 call with a duration of 1 minute

calling subscriber

All the subscribers need to have a connection with the switching system, which makes or breaks any connection, requested by the ______________

transmitter and receiver

A telephone set has a handset that contains a microphone and a speaker, better known as a transmitter and a receiver.

dialing and signaling

All____________ operations are also carried on this single twisted-pair cable.

1871

Antonio Meucci's invention of the telephone in ___________ began the era of telecommunication and marked the start of the telephone timeline that continues to grow to this day.

10000

As many as ___________ telephone lines can be connected to a single central office

4000 Hz

An unloaded twisted pair has an upper cutoff frequency of about ________. But this cutoff varies considerably depending upon the overall length of the cable.

1877

Bell Telephone Company founded. 3000 private

DynaTAC

In 1973, first non-car mobile phone (_________) appears

packet switching

In ____________, messages to be passed are packetized and the connection is used by a call as and when packets are ready

dedicated

In circuit switching, the resources need to be reserved during the setup phase; the resources remain ________ for the entire duration of data transfer until the teardown phase.

teardown phase.

In circuit switching, the resources need to be reserved during the setup phase; the resources remain dedicated for the entire duration of data transfer until the ____________

Traffic engineering

It provides the basis for estimating immediate requirements

Multiprotocol Label Switching

MPLS

Fully Connected Networks

Networks with point-to-point links among all the entities are known as _____________________

Private Branch Exchange

PBX

Subscriber Line Interface Circuit

SLIC

Switching Matrix

The hardware used to establish connection between inlets and outlets is called the____________ or the Switching Network.

microphone

The transmitter is the ____________ into which you speak during a telephone call.

HANDSET

This unit contains a microphone for the transmitter and a speaker or receiver.

Voice over Internet Protocol

VoIP

Centum Call Seconds/Century Call Seconds

CCS

Hundred Call-Second per Hour

CCS is also called __________

Central Office

CO

off the hook

When a call is to be made or to be received, the handset is taken ____________. This closes the switch and connects the telephone circuitry to the local loop. The direct current from the central office is then connected to the telephone, closing its circuits to operate.

connection set-up

creating dedicated channels between the switches

central office

it is where switching circuit is done

AUTOMATIC VOICE LEVEL ADJUSTMENT

. Because of the wide variation in the different loop lengths of the two telephones connected to each other, the circuit resistances will vary considerably, thereby causing a wide variation in the transmitted and received voice signal levels.

EBHC

1 ________ is the average intensity in one or more traffic paths occupied in the busy-hour by one 2-min call or an aggregate duration of 2 min

TU

1 __________ is the average intensity in one or more traffic paths carrying an aggregate traffic of 1 call-hour in 1 hour (the busy hour unless otherwise specified.

1946

250000 women employed as switch board operators for public services and businesses

2011

31% of installed business lines in North America are VoIP based

2015

66.5%of North American businesses lines predicted to be VoIP based

2008

80% of all new PBX Lines are VoIP based

varistor

A )___________ is a nonlinear resistance element whose resistance changes depending upon the amount of current passing through it.

Smart Link

A __________ is a predefined destination path used on a campaign. They are useful for creating default redirects defined by paths set up by the user.

call-second

A __________ is equivalent to 1 call with a duration of 1 second.

switch hook

A _____________ is a double-pole mechanical switch that is usually controlled by a mechanism actuated by the telephone handset.

routing protocol

A _______________ specifies how routers communicate with each other, distributing information that enables them to select routes between any two nodes on a computer network.

analog baseband transceiver

A basic telephone or telephone set is an _____________.

microphone and speaker

A telephone set has a handset that contains a ________________, better known as a transmitter and a receiver.

Switching

Alexander Graham Bell recommended the ___________________ between the subscribers using a switching office that maintains the telephone connections.

switching system

All the subscribers need to have a connection with the ______________, which makes or breaks any connection, requested by the calling subscriber.

unloaded twisted pair

An ___________ has an upper cutoff frequency of about 4000 Hz. But this cutoff varies considerably depending upon the overall length of the cable.

Arrival Rate

Average number of calls initiated per unit time (e.g. attempts per hour) also known as ________

Battery Over-voltage protection Ringing Supervision Coding Hybrid Test signals

BORSCHT

dedicated path

Circuit switching provides a _______________ between the two end points.

Customer Premises Equipment Access Line (Local Loop) Transport Core Central Office/Switch Points of Presence

Elements of the Public Switched Telephone Network (PSTN)

1996

First Voice Over Internet Protocol (VoIP) system introduced - Volitech.

1997

First hosted PBX launched, Virtual PBX, Inc.

1881

First long-distance phone service

1878

First manual switchboard debuts in Boston.

1946

First mobile car-based telephone system introduced

1973

First non-car mobile phone (DynaTAC) appears

Late 2000s

Full integration of landlines, cellular, softphones, and VoIP into hosted PBX business phone systems

Electromechanical Switching Systems

Here, mechanical switches are electrically operated.

Electronic Switching Systems

Here, the usage of electronic components such as diodes, transistors and ICs are used for the switching purposes.

low in number

If the number of telephone sets or the subscribers present is _____________, the type of connection will be a little complex.

multiple paths

If we can allow _____________ inside the switch, we can decrease the number of crosspoints.

Volitech

In 1996, First Voice Over Internet Protocol (VoIP) system introduced - ________

operators

In manual switching, the connections were made by the _____________ at the telephone exchanges in order to establish a connection.

tone dialing system

In most modern telephones, a _________ is used. Known as the dual-tone multifrequency (DTMF) system, this dialing method uses a number of pushbuttons that generate pairs of audio tones that indicate the digits called.

dual-tone multifrequency

In most modern telephones, a tone dialing system is used. Known as the _____________ system, this dialing method uses a number of pushbuttons that generate pairs of audio tones that indicate the digits called.

pulse dialing system

In older telephones, a ___________ was used. A rotary dial connected to a switch produced a number of on/off pulses corresponding to the digit dialed. These on/off pulses formed a simple binary code for signaling the central office.

packetized

In packet switching, messages to be passed are ______________ and the connection is used by a call as and when packets are ready

sidetone

In practice, the hybrid windings are set up so that a small amount of the voice signal produced by the transmitter does occur in the receiver.

call-minute

In telecommunication, a __________ is a unit used to measure communications traffic density.

call-second

In telecommunication, a ____________ is a unit used to measure communications traffic density.

A. B. Strowger

Inventor of the Strowger switching system

Circuit switching

It can also be used for data communications by employing modems which convert data to voice band signals.

Traffic Intensity

It can be measured by averaging periodic counts of the number of calls present during the period, or by summing the duration of calls within the period and dividing by the period length.

single-stage space switch

It can connect an arbitrary idle inlet to an arbitrary idle outlet.

Subscriber Line Interface Circuit

It consists of basic circuits that power the telephones and provides all the basic functions such as ringing, dial tone and dialing supervision

Telephone Traffic

It is also a probability that someone needs to make a call

Traffic Intensity

It is also called TRAFFIC LOAD.

Traffic engineering

It is an analysis of the amount and type of use the proposed system will receive in.

Circuit switching

It is ideal for providing normal voice communications.

Traffic Quantity

It is of particular use for billing or other volume calculations but is not useful by itself.

Traffic Intensity

It is the average number of calls present during a period of time.

Call Intensity

It is used in estimating traffic loads on control equipment where the duration of calls on the traffic-carrying paths is irrelevant.

Traffic Quantity

It represents the total number of channel uses in units of time.

Telephone Handsets SLICs Switching Systems Trunk lines and other media

Major Elements of the Telephone System

teletrofono

Meucci, a brilliant Italian inventor, filed the first one-year renewable notice of an impending patent of the "___________" on December 28, 1871.

December 28, 1871

Meucci, a brilliant Italian inventor, filed the first one-year renewable notice of an impending patent of the "teletrofono" on __________________.

October 1889

Meucci, the true inventor of the telephone, passed away in ___________, before Bell's patent could be dispelled on grounds of fraud.

Erlang

One __________ is the traffic intensity represented by an average of one circuit busy out of a group of circuits over some period of time

Point of Presence

POP

Plain Old Telephone System

POTS

router protocol

Routers connect networks using the Internet Protocol (IP), and OSPF (Open Shortest Path First) is a ____________ used to find the best path for packets as they pass through a set of connected networks.

traffic directing

Routers perform the "____________" functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer.

data packets

Routers perform the "traffic directing" functions on the Internet; ___________ are forwarded through the networks of the internet from router to router until they reach their destination computer.

two-wire, twisted-pair cable

Standard telephones (Subscribers) are connected to the telephone system by way of a ____________ that terminates at the local exchange or central office (CO)

LINE SIDE INTERFACE

Subscriber Line Interface Circuit is also known as the ____________

March 1876

Subsequently, Alexander Graham Bell, who ran experiments at the same laboratory as Meucci, was granted a patent in ___________.

Alexander Graham Bell

Subsequently, ___________, who ran experiments at the same laboratory as Meucci, was granted a patent in March 1876.

on-demand connection

Switching is the provision of an _______________ between two end points.

Packet Switching

Switching method used by the data-link layer

Packet Switching

Switching method used by the network layer

Strowger switching system

The Step-by-step switching system is also called the ______________

receiver

The ________ or earpiece, is basically a small permanent-magnet speaker.

dc power

The _________ for operating the telephone is generated at the central office and supplied to each telephone over the local loop.

hybrid

The _________ is a transformer-like device that is used to simultaneously transmit and receive on a single pair of wires.

transmitter

The _________ is the microphone into which you speak during a telephone call.

frequency response

The _________ of the local loop is approximately 300 to 3400 Hz.

local loop length

The __________ can vary from a few thousand feet up to about 18,000 ft.

dialing circuits

The ___________ provide a way for entering the telephone number to be called.

local loop resistance

The ____________ depends considerably on the length of the twisted pair between the telephone and the central office

Erlang

The _____________ is a dimensionless unit that is used in telephony as a measure of offered load or carried load on service-providing elements such as telephone circuits or telephone switching equipment.

ringer

The _____________ is either a bell or an electronic oscillator connected to a speaker. It is continuously connected to the twisted pair of the local loop back to the central office.

telephone system

The ______________ is also widely used for many other purposes, including facsimile transmission, TV transmission, and computer data transmission.

telephone system

The ______________ is the largest and most complex electronic communication system in the world.

telephone system

The ______________ uses just about every type of electronic communication technique available

Crossbar switching systems

The _______________ have hard-wired control subsystems which use relays and latches.

complete electric circuit

The circuits in the telephone and at the central office form a __________, or loop.

loop

The circuits in the telephone and at the central office form a complete electric circuit, or _________.

analog

The circuits in the telephone and at the central office form a complete electric circuit, or loop.

dc and ac signals

The circuits in the telephone and at the central office form a complete electric circuit, or loop.

telephone system

The connections from the central office go to the "____________" represented by the large "cloud."

cloud

The connections from the central office go to the "telephone system" represented by the large "___________."

Strowger system

The control functions in a ____________ are performed by circuits associated with the switching elements in the system.

local loop

The dc power for operating the telephone is generated at the central office and supplied to each telephone over the ___________.

Holding Time

The duration of occupancy of a traffic path by a call.

300 to 3400 Hz

The frequency response of the local loop is approximately _________.

Switching Network

The hardware used to establish connection between inlets and outlets is called the Switching Matrix or the ______________.

side tone

The hybrid also provides a __________ from the transmitter to the receiver so that the speaker can hear her or his voice in the receiver. This feedback permits automatic voice-level adjustment.

full duplex

The hybrid permits _________, i.e., simultaneous send and receive, analog communication on the two-wire line.

induction coil

The hybrid, which is also sometimes referred to as an __________, is really several transformers combined into a single unit.

switching systems

The introduction of ________________ reduced the complexity of wiring and made the telephony hassle-free.

18000 ft

The local loop length can vary from a few thousand feet up to about _______________.

crosspoints

The major limitation of crossbar switch is the number of ___________ required.

good system

The network connection cannot be simply made with telephone sets and bunch of wires, but a _________________ is required to make or break a connection. This system is known as the Switching System or the Switching Office or the Exchange.

Switching System

The network connection cannot be simply made with telephone sets and bunch of wires, but a good system is required to make or break a connection. This system is known as the Switching System

call rate

The number of times a route or traffic path is used per unit period, or, more properly defined, "the call intensity per traffic path during the busy hour"

full duplex analog communication

The original telephone system was designed for ________________ of voice signals.

electrical path

The primary function of a switching system is to establish an __________ between a given inlet-outlet pair.

two-wire transmission

The regular telephone instrument uses the same pair of wires for both transmitting (talking) and receiving (listening). This is known as ___________

400 ohms

The resistance of the telephone itself also varies over a relatively wide range. It can be as low as 100 ohms and as high as __________, depending upon the circuitry.

electromechanical bell

The ringer in most older telephones is an ___________. A pair of electromagnetic coils is used to operate a small hammer that alternately strikes two small metallic bells.

Inlets

The set of input circuits of an exchange are called _________

telecommunication network

The switching stations provide connection between different subscribers. Such switching systems can be grouped to form a _________________

Telephone Exchange

The switching system, which is also called the ______________, takes care of establishing the calls.

Trunks

The switching systems are connected using lines called the ____________

telecommunication network.

The switching systems are part of a ________________

green

The tip wire is _________ and is usually connected to ground; the ring wire is red.

red

The tip wire is green and is usually connected to ground; the ring wire is _____

hybrid

The transmitter and receiver are independent units, and each has two wires connecting to the telephone circuit. Both connect to a special device known as the _________

tip and ring

The two wires used to connect telephones are labeled _____________.

local loop

The two-wire, twisted-pair connection between the telephone and the central office is referred to as the _________ or subscriber loop. Also referred to as the last mile or the first mile.

subscriber loop

The two-wire, twisted-pair connection between the telephone and the central office is referred to as the local loop or _______________. Also referred to as the last mile or the first mile.

last mile

The two-wire, twisted-pair connection between the telephone and the central office is referred to as the local loop or subscriber loop. Also referred to as the ___________ or the first mile.

first mile

The two-wire, twisted-pair connection between the telephone and the central office is referred to as the local loop or subscriber loop. Also referred to as the last mile or the ___________.

ac voice signals

The_________ are transmitted along with the dc power.

Crossbar switching systems

These subsystems have limited capability and it is virtually impossible to modify them to provide additional functionalities.

Preset Smart Links

This feature eliminates the need to manually setup the Redirect tab where preset Smart Links can be used instead to redirect traffic across multiple campaigns.

telephone number

This means that each telephone must have a unique identification code—the 10-digit _________________ assigned to each telephone.

MPLS

This process consumes time and hardware resources, potentially resulting in degraded performance for real-time applications such as voice and video.

sidetone

This provides feedback to the speaker so that she or he may speak with normal loudness.

space-division switching

This technology was originally designed for use in analog networks but is used currently in both analog and digital networks.

four-wire system

This two-wire system, however, is converted to a ____________, which employs separate paths for each of the directions, to facilitate long distance transmission and switching.

digital techniques

Today, the telephone system is still primarily used for voice, but it employs mostly _____________, not only in signal transmission but also in control operations.

teletraffic engineering and traffic management

Traffic engineering is also known as ______________.

Western Union Affiliate Laboratory

Unfortunately, Meucci's financial troubles combined with misfortune led to the disappearance of his working telephone models from _____________

Erlang

Unit of: Offered load, carried load

Erlang

Voice traffic is measured by the ________, which is the unit of (telephone) traffic intensity.

on the hook

When the handset is "___________," the hook switch is open, thereby isolating all the telephone circuitry from the central office local loop.

open

When the handset is "on the hook," the hook switch is __________, thereby isolating all the telephone circuitry from the central office local loop.

mesh network

When the number of stations N is small, we can simply interconnect the stations with a ____________

switching systems

With the introduction of ______________, the need for traditional connections between the subscribers reduced.

CCS

_________ is a unit of traffic intensity equal to 1/36 of an Erlang

Erlang

_________ is defined as the number of (telephone) call arrivals per mean service time.

Routers

_________ perform the "traffic directing" functions on the Internet; data packets are forwarded through the networks of the internet from router to router until they reach their destination computer.

General routing

__________ :traffic flow between nodes s and d can be split arbitrarily over the paths between s and d

IGP

__________ are protocols aimed at traffic moving around within a larger autonomous system network like a single enterprise's network, which may in turn be made up of many separate local area networks linked through routers.

Telephone trunk lines

__________ are the ones that enable users to make outgoing calls / receive incoming calls in an organization.

Blocking

__________ refers to times when one input cannot be connected to an output because there is no path available between them— all the possible intermediate switches are occupied

Multiprotocol Label Switching

___________ is a protocol-agnostic routing technique designed to speed up and shape traffic flows across enterprise wide area and service provider networks.

OSPF

___________ is designated by the Internet Engineering Task Force (IETF) as one of several Interior Gateway Protocols (IGPs)

Telephone Traffic

___________ is determined by the number of subscribers trying to contact another subscriber

TELEPHONY

___________ is the art of projecting a sound wave thru a given apparatus, transforming the sound wave into an electrical wave, passing the electrical wave over a wire or circuit, and then transforming the electrical wave back into sound wave.

MPLS

___________ was created in the late 1990s as a more efficient alternative to traditional IP routing, which requires each router to independently determine a packet's next hop by inspecting the packet's destination IP address before consulting its own routing table.

Antonio Meucci

___________'s invention of the telephone in 1871 began the era of telecommunication and marked the start of the telephone timeline that continues to grow to this day.

Preset Smart Links

____________ can be used across multiple campaigns once they are configured to simplify campaign setup.

Network Congestion

____________ is defined as the reduced quality of service that occurs when a network node or link is carrying more data than it can handle.

Private Communication System

____________ is designed for limited number of subscribers

Switching

____________ is the provision of an on-demand connection between two end points.

Antonio Meucci

____________, a brilliant Italian inventor, filed the first one-year renewable notice of an impending patent of the "teletrofono" on December 28, 1871.

Interior gateway protocols type 2

____________, distance-vector routing protocols, such as Routing Information Protocol, RIPv2, IGRP.

Exterior gateway protocols

_____________ are routing protocols used on the Internet for exchanging routing information between Autonomous Systems, such as Border Gateway Protocol (BGP), Path Vector Routing Protocol.

Traffic engineering

_____________ is a method of optimizing the performance of a telecommunications network by dynamically analyzing, predicting and regulating the behavior of data transmitted over that network.

Circuit switching

_____________ is ubiquitous in the telephone network.

Telephone System

______________ is a two-way communication system

Telephone Communication System

______________ is designed so that it can connect to any telephone in the world (no compatibility needed) and regardless of distance (range of connection)

Switching network

______________ is the group of connections formed in the process of connecting inlets and outlets.

Traffic Engineering

______________ is the process of distributing traffic flows through the network to achieve load balancing

Call-Second, Call-Minute, Call-Hour

_______________ are units of traffic quantity representing the occupation of a circuit for a second, a minute, or an hour.

Circuit switching

_________________ provides a dedicated path between the two end points.

Alexander Graham Bell

_________________ recommended the Switching between the subscribers using a switching office that maintains the telephone connections.

switch

a device capable of creating temporary connections between two or more devices.

ringer

a device that converts electrical signal from the central office to an audible signal alerting the subscriber that he/she is being called

transport

actual transmission of voice

pulse dialing

also known as loop disconnect dialing, rotary or decadic dialing. The purpose is to set up a series of pulses of current in the telephone circuit.

Subscriber Line Interface Circuit

also known as the LINE SIDE INTERFACE

Switching System

also known as the Switching Office or the Exchange

Switching system

collection of switching elements arranged and controlled in such a way as to set up a common path between any two distant points.

trunk lines

connect switches

tandem office

connects COs without having any direction to the individual telephones

transport core

connects end office switches and core switches

local loop

connects the subscriber/PBX to the COs

transmission regulating unit

consists of a number of capacitors, varistors and resistors whose function is to maintain same speech level regardless of strength of received signals

Circuit-switched network

consists of a set of switches connected by physical links

Mesh and Star topology

conventional methods that connect devices in a network that are impractical and wasteful when the network becomes large

transmitter

converts acoustic energy into electrical energy by means of an input transducer

receiver

converts electrical signal into audible sound or signals, it consists of an output transducer

circuit-switched network

dedicated physical path from transmitter to receiver for the duration of the communication (PSTN)

Telephone Network

group of interconnected switches and subscribers

2007

iPhone debuts

nodes

in switched network, ___________ may be connected to end systems

routing

in switched network, nodes may be used for _______

Point of Presence

inter exchange carrier has its own connection to the local telephone system

Trunk Line

is a direct link between two telephone exchanges or switchboards that are a considerable distance apart

HYBRID

is a two-wire to four-wire circuit for simultaneous two-way conversation on a single pair of wires

CENTRAL OFFICE

it contains all the equipment that operates the telephone

Packet switching

it has started to proliferate into the telephone network under the asynchronous transfer mode (ATM) banner.

Equated Busy-Hour Call

it is a European unit of traffic intensity equal to 1/30 of an Erlang

Traffic engineering

it is the application of knowledge of statistics including queuing theory, the nature of traffic, their practical models, their measurements and simulations to make predictions and to plan telecommunication networks

on-hook condition

refers to a telephone which is not in use

Telephone Traffic

refers to the aggregate of all users' request being serviced by the network

off-hook condition

refers to the handset which is being taken out of the cradle

.Telecommunications

represent the transfer of information, from an entity at one place to an entity at another place, whereas the information can be in the form of data, voice or symbol.

central office

represented by a circle

PBX

represented by a rectangle

subscriber

represented by a triangle

packet-switched network

sends short bursts of data from point to point as needed

CODING

the CO must provide functions that converts Analog to Digital, and vice versa.

RINGING

the CO must provide ringing signal to a receiving station (90 Vrms signal AC at approximately 20 Hz)

BATTERY

the CO provides a DC voltage to the subscriber to operate the telephone. Usually -48 Vdc with resect to ground.

PSTN

the largest and probably the most important communication system in the world

Stored Program Control technology

the method of storing the programs on a processor or computer is called the ___________

Called Subscriber.

the one for whom the call is destined is the ____________

Calling Subscriber

the one who initiates the call is referred to as the ___________________

data transfer

the two parties can transfer data after the connection set-up

OVER-VOLTAGE PROTECTION

these are circuits and components that protect the SLIC from electrical damage

Circuit switching, Packet switching, Message switching

three method of switching:

connection tear down

when one of the parties need to disconnect, a signal is sent to each switch to release the resources

Switched

anyone can possibly communicate with anyone else

signaling

control of calling

ERLANG

it is the international dimensionless unit of traffic intensity.

Telecommunication

means the exchange of information between two distant places

Public Switched Telephone Network

PSTN

circuit-switching

Switching at the physical layer in the traditional telephone network uses the ______________ approach

PSTN

The _____________ can be defined as organizations and facilities involved in connecting a calling telephone to the called telephone regardless of where it might be.

Voice traffic

_________ is measured by the Erlang, which is the unit of (telephone) traffic intensity.

Interior gateway protocols type 1

____________ link-state routing protocols, such as OSPF and IS-IS

topology

basic structure of a local calling area or a typical switched telephone system

switched network

consists of a series of interlinked nodes

touch dialing

each digit is represented by a unique pair of tones

Erlang

named after Agner Krarup Erlang

BORSCHT

seven basic functions of an SLIC:

TEST SIGNALS

to check the status and quality of subscriber lines


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