Melody Murphy
AIL 603
Networking General Information
Excellent work Melody. Very thorough answers.
Category
90%
80%
70%
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Answers are well
Quality of
well written, accurate,
Answers are adequate.
written, accurate, and
Answers
and complete. Most parts Some parts of questions
(100
complete. All parts of
of questions are
are answered.
points)
questions are answered.
answered.
Technical
(10
points)
No violation of
standard rules of
grammar, spelling,
capitalization, and
mechanics.
A few violations of
standard rules of
grammar, spelling,
capitalization, and
mechanics.
Several violations of
standard rules of
grammar, spelling,
capitalization, and
mechanics.
60%
Points
Earned
Answers are poorly
100
written, inaccurate, and
incomplete. Many parts
of questions are
unanswered.
Many violations of
standard rules of
grammar, spelling,
capitalization, and
mechanics.
8
108/110
Total
1. Describe the importance of the following individuals and entities in relation to networks:
Samuel F.B. Morse – in 1837 he patented his electromagnetic telegraph, which sent
signals over the wire. His first telegraph wire was installed between Baltimore and
Washington D.C. and the first electromagnetic telegraph message was transmitted in May
of 1844. Once Morse’s design had been proven operational companies quickly pushed to
install his system and created the first telecommunications network.
Alexander Graham Bell - invented the “electrical speech machine” in 1876 through
which voice was transmitted using electrical current. The telephone as it is known. This
machine made it possible for people to communicate over great distances by just
speaking into a telephone. The invention of this machine caused the swift construction of
telephone exchanges thus starting the network that would eventually span the country and
then the world. In addition to his work on the telephone, Alexander Graham Bell was a
lifelong inventor with other significant inventions. One such invention was the
“photophone” which allowed audio signals to be transmitted using light waves. This
invention, although not particularly useful at the time, was the precursor of today’s fiber
optic and laser technology. In February1876, Bell and Elisha Gray actually took their
competing patents of the telephone to the patent office on the same day. Bell won the
legal fight, thus earning sole credit for the invention. Eventually, the telephone overtook
the telegraph. Over one hundred years later, the telephone is still the primary tool for
communication between people.
Emile Baudot - a French Engineer who developed a telegraph code using a five-unit
combination of keys in either an on or off position. This system was known as “Baudot’s
code” and transmitted entire characters at a time and its use soon exceeded that of Morse
code.
Donald Murray – in 1903 he improved upon the system developed by Emile Baudot, by
building a time-division multiplex system for the British post office. Rather than use
operators to punch keys, Murray used a tape system where the code could be written and
then inserted into a reader which would then send the message through. In addition,
Murray improved upon Baudot’s five-unit code developing a similar five-unit code, but
one that used as few mechanical movements as possible. In 1912, Murray sold his patent
to Western Union & Western Electric, and this development led to the printing telegraph
systems used in the 1920s. In the 1920s AT&T introduced its own system, called
Teletype, which was used in business communication. These systems used a modified
Baudot code, up until the advent of the computer in the 1960s.
Elisha Gray – most commonly known for his work with the telephone. While
Alexander Graham Bell is credited with the invention of the Telephone, there is some
dispute whether Bell or Gray should be credited with the invention. Bell submitted a
patent on the same day that Gray submitted a patent caveat and while Bell eventually was
credited with the invention of the device, some people are skeptical of whether Bell’s
patent design would have worked. Additionally, there are those individuals who believe
that Bell used some of Gray’s ideas in the final product. Although Elisha Gray
contributed to telecommunications through the development of a phone, several others of
his inventions were also noteworthy. Gray’s “teleautograph” used telegraph systems to
transmit handwriting serving as a modern version of today’s fax machine. Additionally,
Gray worked to develop an underwater system of communication through which
messages could be delivered to ships.
Almon Brown Strowger – the inventor of the automatic telephone exchange patented in
1891. Before Strowger’s invention, telephone calls were made with the help of an
operator who connected the call. Strowger’s invention allowed customers to connect
directly and removed the need for a human being switch operator since the switch was
automatic.
Western Union –Western Union began as the New York and Mississippi Valley Printing
Telegraph Company in 1851 but changed its name to exemplify its coast to coast
telecommunications ability in 1856. Through extensive growth, Western Union helped
push the United States into the information age. Western Union completed the first
transcontinental telegraph line, the first stock ticker, the first money transfer service, and
the first credit card. As the telephone supplanted the telegraph, Western Union shifted its
business focus to customer money transfers via wire. In the 1940s, the company
introduced the first inter-city commercial microwave communication system. In 1974,
Western Union launched the first commercial U.S. satellite.
The Carterfone – The Carterfone, which was created by Thomas Carter, is a machine
which can connect two-way radios to land-line telephones. In order to use the
Carterfone, an individual would call the base station on a two way radio. In the late
1960s, the Carterfone was involved in a court case whereby it was ruled that the
Carterfone (and other devices) could connect to the AT&T network as long as it did not
damage the system. The decision allowed non-AT&T products and devices to be
connected to the AT&T network, thus ending the AT&T monopoly. Devices such as fax
machines, cordless phones, and modems could now connect to the system.
2. Discuss the similarities and differences between DSL and cable modems, including speed,
security, advantages, and disadvantages.
Digital Subscriber Lines (DSL) and cable modem come from essentially the same idea.
Both services use existing hardware that is in place in order to provide an additional
service. In the case of DSL, the information is transmitted using the existing copper
cable that carries phone service and in the case of cable modems the information is
carried on existing coaxial cable lines. Because the amount of material necessary to
transmit both telephone and cable service is low compared to the maximum load of their
respective mediums, a portion of the line can be used to transmit other signals.
Speed: cable Internet should be faster than DSL due to higher levels of bandwidth, but
this advantage could be eliminated for technical reasons. In terms of raw speed, cable
modems support approximately 30 megabits per second (Mbps) while DSL supports only
10 Mbps.
Security: DSL and cable offer the same level of security, since both allowed the
capability to be online at all times. Many, however, believe that DSL is more secure than
cable, since cable users in a region are all connected to the same network, or LAN.
Concerns aside, if users take the proper security precautions (installing network firewall
software, anti-virus software, etc.) then security should be roughly equal.
Advantages and Disadvantages: They both have great performance. Cable should
provide better performance due to better bandwidth and the fact that distance to a central
office has no impact on performance. With DSL, performance is largely tied to your
location in relation to a central office. The further you are from a central office, the
slower the performance.
3. TV remote controls were some of the first devices to use infrared signals generated by
light-emitting diodes. However, TV remote controls date back to 1950 when Zenith
introduced the first remote control, the Lazy Bones. Using the Internet and printed
sources, trace the development of the TV remote control as one of the pioneers of infrared
technology. Explain how other technologies, such as radio frequency and ultrasonics, were
proposed, but rejected. What are the capabilities and limitations of today’s infrared
remotes?
The first television remote control, the “Lazy Bones,” was created by Zenith in the 1950s.
The Lazy Bones actually was not a wireless remote, but was connected to the computer by a
cable. The remote was able to turn the tv on and off, and change channels, but the customers did
not like the remote because people often tripped over the cable. In 1955 Zenith engineer Eugene
Polley invented the “Flash-matic,” the first wireless remote. The “Flash-matic” utilized four
photocells in the four corners of the television. A flashlight was directed into specific corners on
and off, change the volume, or tune the tv. The “Flash-matic” proved unpopular because people
often forgot which corner handled specific commands, and the television was so light sensitive
that the channel change or the television would simply turn off due to sunlight. The next year,
Dr, Robert Adler Zenith developed the “Zenith Space Command” remote which utilized
ultrasonics, and this remote would remain in use for the next twenty-five years. By the early
1980s, scientists realized a new type of remote was needed because the high frequency
ultrasound used by the remote was sometimes heard by people and dogs, and noises sometimes
changed the television channel or turned it on or off. Therefore, a change, once again led by
Zenith, was toward infrared remote technology. Today, most television remotes use infrared
technology. The infrared remote uses a low frequency light beam, a beam so low the human eye
cannot detect it. There are a few limitations of the infrared remote: 1) clear line of sight from the
remote to the television sensor; 2) can block common materials, people, or animals; 3) the longer
the distance, the lower the effectiveness; 4) direct sunlight, rain, fog, dust, or pollen can impact
transmission. Still, infrared technology is generally reliable and low cost, is usually more secure,
and is not negatively impacted by noise.
4. Describe IP addresses, including what they are, how they work, how to figure out your
own IP address, and fixing IP addressing problems.
IP address: is an identifier for a computer or device on a TCP/IP network. It is a numeric address
that is given to servers and users connected to the Internet. IP stands for Internet Protocol. Networks using
the TCP/IP route messages based upon the IP address of the destination. The format of an IP address is a
32-bit numeric address written as four numbers separated by periods. Each number can be 0 to 255.
Isolated networks can assign IP addresses at random as long as each address is unique. Connecting a
private network to the Internet requires using a registered IP address. The IP address consists of two parts,
one in the network and the other identifying the host. This information is important because it helps you
identify the correct Network class. IP addresses generally fall into three categories: Class A, Class B, and
Class C. Users are assigned an IP address by their Internet Service Provider (ISP) when they go online. It
can be a static IP, which is the same number each time a user signs on, or it might be a newly assigned
number each time depending on what’s available. For servers, it is translated into a domain name by a
Domain Name Server (DNS).
In order to identify your own IP address, the user must click on “Start,” “Control Panel,” and then
“Network Connections.” In the Network Connections window, find your network connection. Usually
this will be labeled as Local Area Connection for a wired connection, or if connecting with a wireless
connection, it will be labeled Wireless Network Connection. The users then will right-click on the
appropriate network connection and select “Status” from the menu that appears on the “Network
Connection Status” window. Click the “Support” tab on this window to display the IP address.
In order to fix or repair IP addressing problems, the user can follow the same steps for identifying
their own IP address, but once you have clicked on the “Support” tab, simply click the “Repair” button.
This helps if the user is having difficulty connecting the Internet Connection Sharing (ICS) host to the
Internet to obtain refreshed IP address configurations from the ISP. “Repair” can also be used to force a
connection to refresh its IP address configuration from the ICS host if a computer on a network is unable
to communicate with other network computers.
5. Describe the differences between analog and digital signals.
Analog signals: a sine wave system which carries information, and is a continuous electrical
signals that changes over time. Signals of varying frequency or amplitude are added to carrier
waves with a given frequency of electromagnetic current to produce a continuous electric wave.
The term "analog signal" came about because the variations in the carrier waves are similar, or
analogous, to that of the voice itself.
Digital signals- square waves and are non-continuous and change in individual steps. They
consist of pulses or digits with discrete levels or values. The value of each pulse is constant, but
there is an abrupt change from one digit to the next. Digital signals have two amplitude levels
called nodes. The value of which are specified as one of two possibilities such as 1 or 0. Positive
is expressed as the number 1, while non-positive is expressed as the number 0. Numbers that are
expressed as a string of 0’s and 1’s are called binary numbers. Every digit in a binary number is
referred to as a bit and represents a power of two. Digital signals represented by discrete
variations can be transmitted faster and more accurately than analog signals.