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					Deann K. Stone                                                        AIL 603

General Information

Using Microsoft Word, answer the following questions:

1. Describe the importance of the following individuals and entities in relation to
networks:

      Samuel F.B. Morse – Only 9 years after Samuel Morse sent the first
       telegraph message, he began the development of a telegraph network. By
       1853 only one state east of the Mississippi, Florida, was not connected by
       telegraph. By 1861, telegraph lines connected the American continent; by
       1866, the transatlantic cable connected America and Europe.
      Alexander Graham Bell – In 1875 Alexander Graham Bell, building on
       the inventions of several before him (Meucci, Bourseul, Reis, Manzetti,
       Ellison), builds the first telephone and opens up new networking
       opportunities.
      Emile Baudot - Not long after Morse's Telegraph, French inventor Emile
       Baudot developed a printing telegraph machine which used a typewriter
       style keyboard. Baudot used a different type of code for his system
       because Morse code didn't lend itself to automation.. Baudot used a five
       bit code to represent each character, this would normally only give 32
       possible combinations (00000 to 11111 = 32). To this day, the speed of
       serial communications is still measured in Baud rate, after Emile Baudot.
      Donald Murray – Born a mechanic in 1866 Donald Murray joined the
       staff of the Postal Cable Company in 1898. Two years later, he came to
       London and worked at the General Post Office on the development of his
       first system of printing telegraphy. He then designed a system of multiple
       telegraphy which possessed important advantages over that of Baudot;
       his phonic wheel motor, in combination with Baudot's epicyclic correcting
       train gave such excellent synchronism that it was adopted by the French
       Telegraph Administration. In 1925 he was awarded the Paris Exhibition
       Premium for his Institution paper on "Speeding up the Telegraphs; a
       Forecast of the New Telegraphy".
      Elisha Gray - On Feb. 14, 1876, Gray filed with the U.S. Patent Office a
       caveat (an announcement of an invention he expected soon to patent)
       describing an apparatus 'for transmitting vocal sounds telegraphically.'
       Alexander Graham Bell had only two hours earlier applied for an actual
       patent on an apparatus to accomplish the same end. It was later
       discovered that the apparatus described in Gray's caveat would have
       worked, while that in Bell's patent would not have. After years of
       litigation, Bell was legally named the inventor of the telephone, although
       to many the question of who should be credited with the invention
       remained debatable.
      Almon Brown Strowger - Almon Strowger was a local undertaker who
       was described as "eccentric, irascible and even mad." In 1888 he was
       motivated to invent an automatic telephone exchange after having
       difficulties with the local telephone operators who he claimed were
       sending calls to his competitor rather than his business. He patented the
       automated telephone exchange in 1891. The first automated telephone
       exchange was installed in La Porte, Indiana on November 3, 1982.
      Western Union -. The company, The New York and Mississippi Valley
       Printing Telegraph Company, founded in Rochester, NY in 1851 was later
       named Western Union. The new name, suggested by Ezra Cornell,
       signified the joining of telegraph lines from coast to coast. Western Union
       completed the first transcontinental telegraph line in 1861; formed the
       Russian American Telegraph 1865; introduced the first stock ticker in
       1866; and a standardized time service in 1870. In 1871 the company
       introduced its money transfer service. In 1914 Western Union offered the
       first charge card for consumers; in 1923 it introduced teletypewriters to
       join its branches. Singing telegrams followed in 1933, intercity fax in
       1935, and commercial intercity microwave communications in 1943. In
       1958 it began offering Telex to customers. In 1964, Western Union
       initiated a transcontinental microwave beam to replace land lines.
       Western Union became the first American telecommunications corporation
       to maintain its own fleet of geosynchronous communication satellites,
       starting in 1974.
      The Carterfone - Thomas Carter invented the Carterfone, an invention
       that connects a two-way mobile radio system to the Public Switched
       Telephone Network (PSTN). It was electrically connected to the base
       station of the mobile radio system, and the electrical parts were encased
       in bakelite. When someone on the radio wished to speak to someone on
       phone, or "landline", the station operator at the base would dial the
       number and place the handset on the Carterfone. The device was
       therefore acoustically connected to the Public Switched Telephone
       Network, and did not have the capacity to damage the PSTN.

2. Define the following terms:

      RS-232C - Short for recommended standard-232C, a standard interface
       approved by the Electronic Industries Alliance (EIA) for connecting serial
       devices. In 1987, the EIA released a new version of the standard and
       changed the name to EIA-232-D. And in 1991, the EIA teamed up with
       Telecommunications Industry association (TIA) and issued a new version
       of the standard called EIA/TIA-232-E. Many people, however, still refer to
       the standard as RS-232C, or just RS-232.
      USB - Universal Serial Bus is a serial bus standard to interface devices. It
       was designed for computers such as PCs and the Apple Macintosh, but its
       popularity has prompted it to also become commonplace on video game
       consoles, PDAs, cellphones; and even devices such as televisions and
       home stereo equipment (e.g., mp3 players), and portable memory
       devices.
      FireWire/IEEE 1394/iLink - IEEE 1394 (aka. FireWire and iLINK) is a
       high-bandwidth isochronous (real-time) interface for computers,
       peripherals, and consumer electronics products such as camcorders,
       VCRs, printers, PCs, TVs, and digital cameras. With IEEE 1394-compatible
       products and systems, users can transfer video or still images from a
       camera or camcorder to a printer, PC, or television, with no image
       degradation.
      ISDN - Integrated Services Digital Network, an international
       communications standard for sending voice, video, and data over digital
       telephone lines or normal telephone wires. ISDN supports data transfer
       rates of 64 Kbps (64,000 bits per second).
      DSL - DSL is a very high-speed connection that uses the same wires as a
       regular telephone line to connect to the internet.
      ADSL - Asymmetric Digital Subscriber Line is a form of DSL, a data
       communications technology that enables faster data transmission over
       copper telephone lines than a conventional modem can provide. It does
       this by utilizing frequencies that are normally not used by a voice
       telephone call, in particular, frequencies higher than normal human
       hearing. This signal will not travel very far over normal telephone cables,
       so ADSL can only be used over short distances, typically less than 2 km.
       Once the signal reaches the telephone company's local office, the ADSL
       signal is stripped off and immediately routed onto a conventional internet
       network, while any voice-frequency signal is switched into the
       conventional phone network. This allows a single telephone connection to
       be used for both ADSL and voice calls at the same time.
      Cable Modem - Cable modems compete with technologies like ADSL.
       The modem allows a computer network and cable television to share the
       same lines.

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 the
capabilities and limitations of today’s infrared remotes?
Remote control technology was developed for military use and first entered
American households in 1956. Zenith developed the Lazy Bone, a wired remote
            control in 1950. Consumers did not like the bulky wire, which caused
            tripping, and there weren’t very many channels to choose from.
            Eugene Polley, a Zenith engineer, created the "Flash-matic," the first
            wireless TV remote, in 1955. The Flash-matic operated by means of
            four photocells, one in each corner of the TV screen. The viewer used
a directional flashlight to activate the four control functions, which turned the
picture and sound on and off and turned the channel tuner dial clockwise and
counter-clockwise. However, the Flash-matic had problems working well on
sunny days, when the sunlight could change channels randomly. Another Zenith
engineer, Dr. Robert Adler, then invented the Zenith Space Command. The
                device, based on ultrasound technolgoy, was large due the six
                vacuum tubes required to make it work. With the invention of the
                transistor, the size of the device decreased, but he clicking noise
                made by the ultrasonic device sometimes caused dogs to bark!
                The pitch and frequency of the device fine tuned, however some
                women could still hear it and there was one incident when a toy
xylophone changed the television channel! In the early 1980s, when
semiconductors for emitting and receiving infrared radiation were developed,
remote controls gradually switched to that technology which, as of 2006, is still
widely used. Infrared remotes only have a range of about 30 feet and require
“line-of-sight” in order to work. Remotes using radio technologies, such as Bose
Audio Systems and those based on Bluetooth also exist. These do not require
“line-of-sight”, allowing the device to work around corners or even through walls.

4. Locate an ASCII chart on the Internet or in a book. Look up the ASCII value
for all of the letters of your first name. ASCII values will range from 65 to 122.
Note that there is a difference between uppercase and lowercase letters. After
having determined the ASCII value for each letter, convert each value to binary
code. Because all ASCII values are between 0-255, the number of bits needed to
represent any ASCII code is eight. As an example, the name Lisa begins with
“L.”. The ASCII value of uppercase “L” is 76 with a binary equivalent of
01001100.

         Letter                       ASCII                    Binary Code
           D                           68                       01000100
           e                           101                      01100101
           a                           97                       01100001
           n                           110                      01101110
           n                           110                      01101110
5. Describe the differences between analog and digital signals.

Analog signals are continuous electrical signals that vary in time as shown in figure
4a. Most of the time, the variations follow that of the non-electric (original) signal.
Therefore, the two are analogous hence the name analog.




                              Figure 4a: Analog Signal

Not all analog signals vary as smoothly as the waveform shown in Figure 4a. Analog
signals represent some physical quantity and they are a ‘MODEL’ of the real quantity.

                                  Digital Signals

Digital signals are non-continuous, they 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, HIGH or LOW, TRUE or FALSE and so on. In reality, the
values are anywhere within specific ranges and we define values within a given
range.




ICT, Technologies, Chapter 3, Module 2, Retrieved September 12, 2006,
http://cbdd.wsu.edu/kewlcontent/cdoutput/TR502/page8.htm

				
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