Transcript Telecommunications and the Information Age - Overview

Telecommunications and the
Information Age - Overview
• Course and Syllabus Review
• Learning Module Review
• Communications and
Telecommunications between 1845
and 1920
• Telecommunications between 1920
and Now
Telecommunications and the
Information Age - Overview
• Course and Syllabus Review
• Review the course orientation and syllabus
• Take the Syllabus Quiz
• Contact Info
• WEB Page: sites.csn.edu/jmiller
• Every one log-on and go to the site
• Office and Office Hours
• CY 2713
• Office hours listed on Web Page
• [email protected]
• Textbooks:
• Required: Electronic Communication Systems, Beasley, Hymer, &
Miller, Publisher: Pearson, ISBN:01312988636
Telecomm & the Info Age - Overview
• Course and Syllabus Review
• Text Books:
• Optional: Telecommunications and Data Network Handbook, by
Ray Horak, Publisher: Wiley, ISBN: 9780470041413
• Outcomes
• Per paper Syllabus
• Weekly Assignments
• Per Weekly Learning Module
• Learning Module Review
• Each week except for the Mid-Term and Final’s weeks
have a separate Learning Module
• Located on the Course WEB Site
• Reachable through either the WebCT course or at
http://sites.csn.edu/jmiller
Telecomm & the Info Age - Overview
• Learning Module Review
• Learning Modules Contains
• Overview of the materials covered in the module
• Learning outcomes
• Reading Assignment with Reference slides
• Reference to that modules discussion questions
• Any Additional materials or WEB Sites related to the
module’s topics
Communications and Telecomm
between 1845 and 1920
• The Mid 1800’s were a time of great
discoveries and the idea that
communications could take place over long
distances using wire and electricity was just
being imagined.
• Several discoveries during this time were
critical to the sending communications
signals across wires using electricity
Communications and Telecomm
between 1845 and 1920
• Batteries
• Developed by Italian Alessandro Volta in 1799
• Electromagnets and Induction
• 1820 Danish physicist Hans Oersted showed:
• Current through a wire, produces a magnetic field around wire.
• British scientist Michael Faraday
• When you move a loop of a wire in a magnetic field, a little bit of
current flows through the loop for just a moment.
• This is called induction.
• Faraday constructed a version of it called the induction ring
• Michael Faraday demonstrated a electric motor.
Communications and Telecomm
between 1845 and 1920
• Electromagnets and Induction
• British scientist Michael Faraday
• In 1834 Thomas Davenport designed a motor
that was strong enough to run a small
printing press
• John Henry developed a electro magnet
• It could do heavy work, such as lifting
hundreds
of pounds of metal. With his demonstration
• Henry really began to transform electricity
into something that people could use every
day.
Picture from IEEE Virtual Museum
Communications and Telecomm
between 1845 and 1920
• Communications
• Telegraph
• However, the most successful practical
early use of electricity in the 19th century was a simple
communication device called the telegraph.
• This new form of communication ushered in the era of electrical
communication and brought electricity to the forefront of the
public’s attention.
• In 1837, English scientist Charles Wheatstone opened the first
commerical telegraph line between London and Camden Town, a
distance of 1.5 miles.
• Building on Wheatstone's ideas, Samuel Morse, an American
artist and inventor, designed a line to connect Washington, DC
and Baltimore, Maryland in 1844.
Picture from IEEE Virtual Museum
Communications and Telecomm
between 1845 and 1920
• Communications
• Telegraph
Copyright (c) 2007 by Pearson Education, Inc.
All rights reserved.
• By 1865 Western Union was the dominate telegraph company in
the US
• Trans-Alantic telegraph links before 1869
Communications and Telecomm
between 1845 and 1920
• Telephone
• In 1875, Bell discovered a way to
convert sound waves to an
undulating current that could be
carried along wires.
• This helped him invent the
telephone.
• At first, telephones were connected
in pairs.
• You could call only one person, and
they could only call you.
• First exchange was in 1878.
• In 1891 an automatic exchange was
invented.
This experimental telephone was
demonstrated by Alexander Graham Bell in
1876. It uses the interaction between an
electromagnet and a diaphragm to convert
sound waves into electrical signals and back
again. A person speaking into the transmitter
causes the parchment diaphragm to vibrate.
Mounted in the center of the diaphragm is a
metal button (seen in the photo). As this
button vibrates within the field surrounding
the electromagnet, it causes fluctuations in
the current moving through the
electromagnet. The fluctuating current travels
through a telephone wire causing matching
fluctuations in the receiver’s coils. These
cause the receiver’s diaphragm to vibrate,
thus reproducing the original sound.
Courtesy: Smithsonian Institution.
Picture from IEEE Virtual Museum
The box telephone, the first functional phone
installed at a customer location. (Photo courtesy
of AT&T, Warren, NJ)
Switchboards:
The switchboard was used to
connect subscriber lines
together for the duration of
the call. A light or dropdown
door was used to signal an
incoming call, at which point
the switchboard operator
connected one port to the
second using a plug cord
inserted into each of the two
jacks. Upon completion of a
call the operator removed the
plug cord
Switchboards:
The switchboard was the first switch used to connect two subscriber’s
telephone conversations. The switchboards shown are tied together with
trunk connections. The operator connects the first subscriber’s port to
one of the trunk connections, then connects the second subscriber to the
same trunk creating a complete connection between the two subscriber’s.
Communications and Telecomm
between 1845 and 1920
• Telephone
• Trunk Circuits
• Trunk lines were originally used to connect switchboards located in one
central office
• A trunk line is common to all connected switchboards
• Only the ones that are patched into the trunk line at any moment are
connected
• Later they were used to connect central offices together
• The hierarchy of switches eventually was used for long distance calling
Some switchboard operators wore
roller skates to help them move quickly
up and down the rows of
switchboards.
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
Communications and Telecomm
between 1845 and 1920
• Telephone
• Long Distance
• Main problem was that the signal weakened with distance,
disappearing if the telephone lines were too long.
• A solution was found in 1912 with a way to amplify electrical
signals, and transcontinental phone calls were possible.
• A test took place in 1914, and the next year,
• Bell, who was in New York, called Watson, who was in San
Francisco.
• He said the same thing he had said during the first phone
conversation. Watson’s answer?
• “It will take me five days to get there now!”
Communications and Telecomm
between 1845 and 1920
• Telephone Switches
• First Automatic (aka mechanical) telephone
switches • Strowger or Step-By-Step Switches
• First developed by a mortician named
Strowger in Kansas City, Missouri
• Invented in 1891
• Same Functionality exists
In modern telephone
Switches
• Switch receives a dialed
number
• Looks up the dialed number and
connects the two lines
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
Communications and Telecomm
between 1845 and 1920
• Telephone Signaling
• A function required in every telephone network
• Some common examples of telephone signaling
• Ringing of a phone when there is an incoming call
• The dialed digits communicated to the switch identifying the called
telephone
• Dial tones
• Busy signals
• Unheard call setup and teardown signals
• etc.
• Before automatic switches the signaling was verbal information
pasted to switchboard operators
• Today it is call control information imbedded in Voice over IP packets
Communications and Telecomm
between 1920 and Now
• Technical Breakthroughs related to
Telecommunications
• Some of the more critical breakthroughs by Bell Labs
• Talking movies – 1926
• FM Radio – 1933
• Transistors – 1947
• Regulations
• Communications Act of 1934
• Updated the Interstate Commerce Commission's Kingsbuery
Agreement of 1913 – Bottom of page 10 of the textbook
• Created Federal Communications Commission (FCC) and each state
created Public Service Commissions (PSCs) or Public Utility
Commissions (PUCs)
• The FCC, PUCs and PSCs, and ATT pushed for universal service
• Long Distance charges used to subsidize rural phone services
Communications and Telecomm
between 1920 and Now
• Regulations
• Changes to Kingsbury Agreement allowing ATT to
control what is attached to their network
• Hush-a-Phone passive privacy protection device
manufacturing company defeated ATT in court and its product
was allowed to be used with ATT phones starting in 1958
• Caterfone Company won a law suit against ATT and their
product that linked a telephone to a two-way radio – 1968
• The court ruling also allowed the connection of communications
equipment that didn’t adversely effect the telephone system
• Companies such as Northern Telecom, Mitel, and Rohm started
selling key systems, PBX, and handsets
• 1969 Court Decision - permitted MCI to provide limited
competition to AT&T
Communications and Telecomm
between 1920 and Now
• Regulations
• 1984 - deregulation of AT&T
• 1996 - Telecommunications Act
• Practically overnight, the local telephone industry in the U.S. went
from a highly regulated and legally restricted monopoly to open
competition.
• Local service in the U.S. is now open for competition
• RBOCs are now permitted to provide long distance services.
•
1997 - International agreement - 68 countries to reduce
telecommunication regulation
• Post 2000 the FCC removed the basic and enhance separation of
Incumbent Local Exchange Carriers services and started the
decline of the Completive Local Exchange Carriers that depended
upon discounted prices for ILEC basic services
Communications and Telecomm
between 1920 and Now
• Regulations
• In 2005 the FCC required that VoIP provide Emergency
911 service.
• Technological Milestones
• Central Office
• During the 1920 – 1950 period the biggest change was the
replacement of Strowger switches by crossbar switches that
had larger capacity
• During the 1920 – 1950 Direct Distance Dialing started and
operators were no longer required for long distance calls
• During the 1950 – 1970 period the electronic/digital switch was
developed and the replacement of crossbar switches started
• During the 1970 – 1990 period the most of the crossbar
switches were replaced by electronic/digital switches
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Central Office
• During the 1990 – 2000 period the further introduction of
digital switches decreased manpower needs
• During the 1990 – 2000 period fast packet switches which
relied on several protocols such as frame relay, ATM, and IP
• Transmission Network
• During the 1920 – 1950 period the biggest change was the
introduction of the Frequency Domain Multiplexer (FDM)
• Pre FDM 24 trunk lines required 24 pairs of wires between the
two central offices – Post FDM only two-pairs were required for
24 truck lines between central offices
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
From: Introduction to Telecommunications,
2/e By M.A.Rosengrant
• During the 1950 – 1970 period the majority of long-haul
network lines were moved from copper cable to microwave
links
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
• During the 1970 – 1990 period the multiplexing methods were
changed from FDM to a digital type method.
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
• Digital multiplexing methods was time division multiplexing
and it required that electrical voice signals are converted into
into digital data
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
• The electrical voice signals are converted into digital
information using Pulse Code Modulation which was invented
by an ITT scientist Alec Reeves
• By the 1980’s Fiber Optic (FO) circuits were replacing
microwave link and copper cable links
• Weather and electromagnetic radiation have no effect on digital
voice signals on FO circuits
• Fewer repeaters are required
• Each pair can carry many more calls
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
• 1990- 2000 period
• By 2000 Synchronous Optical Network (SONET) connected most
of the US
• The SONET standard was developed in 1988 and allows for the
interconnection and functioning of FO equipment from different
vendors
• Improved terminating equipment and FO cables allow dramatic
increases of the call capacity of a FO pair – at the time 129,024
calls per pair
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Transmission Network
• 2000 – Present period
• The converged network, i.e., voice, data and video over the same
IP based network.
• Wave Division multiplexing on FO cables enabled a dramatic
increase of capacity
• Outside Plant
• 1920 -1950
• Cable termination and installation procedures were standized
• 1950 – 1970
• The introduction of polyurethane-insulated cable to replace
paper insulated cable
• 1970 – 1990
• The use of Digital Loop Carriers (DLC) to minimize copper cable
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Outside Plant
• 1970 – 1990
Digital loop carrier
systems are deployed
to help reduce the
amount of copper cable
needed to feed specific
areas in a region. The
DLC connects to the
central office via T1
circuits that carry the
many voice channels
from the individual
subscribers.
Pictures Copyright (c) 2007 by Pearson
Education, Inc.
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Outside Plant
• 1990 – 2000
• Continued improvements in equipment and procedures
• Long Distance
• 1920 – 1990
• By 1950 all areas of the US were able place long distance calls
• 1950 – 1970
• Satellite communication links
• First “800” calls (1968)
• 1970 – 1990
• Vastly increased capacity due to FO cables
Communications and Telecomm
between 1920 and Now
• Technological Milestones
• Long Distance
• 1990 – 2000
• Continued increased capacity due to FO cables and price
competition
• Technological Milestones
• 2000 – Present
• The converged network, i.e., voice, data and video over the same
IP based network.
• Wave Division multiplexing on FO cables enabled a dramatic
increase of capacity