An Information Superhighway prior to the internet was…

1. An Information Superhighway prior to the internet was… Electrical Telegraph – Passing current in wires to transmit information over long distances. With the discovery that electrical currents can induce magnetic fields, there was now an way to transmit electrical signals over wires and to detect small currents traveling in wires at a receiver. Shortly thereafter came Wireless Telegraph; Telephone; and Radio

2. The First Info. superhighway was the widespread release of information as a result of the Printing Press in the 1400’s Johannes Gutenberg’s movable-type printing press promoted the spread of knowledge. Information did not have to come from clerics and royalty. A&E Network voted Johannes Gutenberg "Man of the 2nd Millennium" Wikipedia

3. Impacts of the Printing Press • Rise in Protestant Reformation • Availability of Greek and Roman classic literature, leading to the Renaissance • Decline in the use of Latin • Greater dissemination of scientific information • Higher literacy rates

4. Printing Press & the Chinese Language • Chinese developed Woodblock Printing (200AD) and Movable type printing. • Block printing was suitable since character alignment is not critical with the Chinese language. • Moveable Type printing was impractical with 5000 basic Chinese characters European languages offered distinct advantages over Chinese, leading to wider dissemination of written materials and greater range of materials. http://en.wikipedia.org

5. Brief Timeline of telegraph and radio 1833: Electrical Telegraph – using electricity in wires to transmit information. 1835: Relay is developed 1866: First transatlantic cable is successfully laid on ocean floor, to be used for the electrical telegraph. 1876: First telephone (wires used to transmit voice, not just Morse codes) 1894: First use of wireless telegraph (transmitting Morse codes without the use of wires) 1906: First radio broadcast (transmitting voice without wires)

6. Electrical Telegraph • In 1832, Baron Schilling (a Russian from Estonia) devised a communication device using wires to transmit signals between rooms of his home • In 1835-6, his system was tested at distances of 5 km using underwater cable. • First to use binary codes to transmit messages.

7. Samuel Morse develops a code comprised of dots and dashes. Morse is granted a patent in 1837 for his electromagnetic telegraph. A weak current from The sender activates a relay that connects a battery to the sounder. A series of Clicks and Clacks Were transmitted to the receiver.

8. Sounder – Self Interrupting Circuit Switch or Relay Voltage Source http://home.howstuffworks.com/doorbell2.htm

9. Using $30,000 obtained from congress, Morse builds a 40 mile telegraph line from Washington DC to Baltimore. In 1844, the first message is sent: “What hath God wrought?” .-- .... .- - / .... .- - .... / --. --- -.. / .-- .-. --- ..- --. .... - http://morsecode.scphillips.com/jtranslator.html Morse code translator

10. Recall Maxwell’s Equations 1. Like charges repel, unlike charges attract 2. Magnetic fields always have two poles (positive and negative) 3. A moving/changing magnetic field can produce current. 4. Moving electrical charge (current) can produce a magnetic field.

11. Maxwell predicts Electromagnetic Radiation Wikipedia.com An electromagnetic wave exists when the changing magnetic field causes an electric field which then causes another changing magnetic field, and so on forever. These oscillating fields together form an electromagnetic wave. An electromagnetic wave will travel at the speed of light and continue on forever until absorbed.

12. Hertz’s Spark and Loop Experiment In 1888, Heinrich Hertz proved Maxwell’s theories with this experiment. Hertz said, “I don’t see any useful purpose for this invisible electromagnetic energy.” In 1864 Maxwell proves mathematically that changes in electrical current will produce an electromagnetic wave; a radiation (radio) wave.Hertz then demonstrates existence of electromagnetic waves.

13. 1866 – Laying the transatlantic cable • Five attempts to lay cable in 12 years • 1866 cable was able to transmit eight words a minute http://www.cmhg.gc.ca

14. Wikipedia Alexander Graham Bell and the Telephone • Very interested in assisting the deaf. Both his mother and wife were deaf. • Devised hearing aides • Taught in a school for the deaf • Used the concept of Electromagnetic Induction to convert sound waves (pressure wave) into electrical signals in 1876

15. Bell patents the electro-magnetic transmission of vocal sound by undulatory electric current in 1876 http://sln.fi.edu Microphone http://www.acmi.net.au

16. Bell’s First Telephone-Liquid Transmitter The sound wave vibrates the diaphragm that in turn moves a rod up and down. This changes the resistance making the current change in consort with the sound wave. http://www.juliantrubin.com

17. With an Electro-Magnetic Receiver

18. A Watershed MomentMarch 10, 1876 "I then shouted into M [the mouthpiece] the following sentence: 'Mr. Watson--come here--I want to see you.' To my delight he came and declared that he had heard and understood what I said." Wikipedia

19. Bell had other iterations of transmitters and receivers using various technologies. http://www.ctol.org.uk

20. It is important to note that there is no one "inventor of the telephone" . Bell was merely the first to patent the telephone, an "apparatus for transmitting vocal or other sounds telegraphically", 16 years afterAntonio Meucci, who did not have $10 to file a patent, demonstrated his electro-magnetic "teletrofono" in New York in 1860. Wikipedia A 2002 a resolution by the U.S. House of Representatives, gave its endorsement of Antonio Santi Giuseppe Meucci as the originator of the telephone. HR 269

21. Timing is everything. Elisha Gray knew all too well just how true that old adage could be. On February 14, 1876, the day that Alexander Graham Bell filed an application for a patent for his version of the telephone, Elisha Gray applied for a caveat announcing his intention to file a claim for a patent for the same invention. Elisha Gray of Ohio PBS.org Bell’s patent has been defended in 587 lawsuits.

22. Thomas Edison makes improvements Bell’s telephones produced weak electric signals limiting the quality and distance of the message. Emile Berliner and soon thereafter Thomas Edison improved the sensitivity of sound detection at the transmitter (microphone) by replacing the parchment membrane with a disc of compressed carbon set between metal plates. The electrical resistance of carbon is extremely sensitive to the minute pressure changes caused by sound waves. http://www.porticus.org

23. The Carbon Transmitter (microphone) This Technology, improved later by substituting granulated carbon and then roasting the granules—became a basic component of telephones for almost a hundred years. http://www.beatmag.net

24. When the carbon is pulsated by a sound wave, the resistance of the carbon button changes slightly. This creates an electrical signal in the wires that matches the sound wave. http://www.exnet.btinternet.co.uk

25. The Telephone Receiver http://www.privateline.com

26. The Current travels to the receiver and goes through a coil of wire. This induces a magnetic field which in turn causes the diaphragm to vibrate. This is a simple speaker. http://www.exnet.btinternet.co.uk

27. MIC – microphone REC - receiver http://www.telephonecollecting.org

28. http://www.exnet.btinternet.co.uk/T293/telephones.htm Good simple explanation of 20th century phones.

29. Rotating Sprocket Dialing a number sends out pulses or clicks to the telephone exchange. Dialing a ‘2’ will result in the switch opening and closing twice. The exchange connects you with the line called. http://www.exnet.btinternet.co.uk

30. Try this experiment at home Dial 411 by pressing on the switchhook (the button on the phone’s cradle) • Hit the switchhook 4 times fast • Hit the switchhook once, briefly wait, then • Hit the switchhook again once. You just dialed 411

31. Modern Phones • Piezoelectric transducers convert electrical signals into mechanical stress • Electret Microphones replace carbon based mics • Touchtone phones introduced in 1963. Each button produces a DTMF tone. DTMF – Dual Tone Multi- Frequency

32. First wireless communications in 1895 using Morse codes Alexander Popov sent over a distance of 600 meters Guglielmo Marconi sent messages to his brother within the grounds of his Bologna estate. http://www.mlahanas.de http://en.wikipedia.org

33. The Coherer Tube (filled with iron shavings) was the Receiver When the coherer detected a radio wave, the resistance in the tube changed causing the bell to ring. The wave was created by a distant spark.

34. Guglielmo Marconi obtains a patent for wireless telegraphy in 1896 In 1901, the letter ‘S’ is sent from Cornwall to Newfoundland. This proved that wireless telegraphy was possible (and fast) over long distances. All electromagnetic waves travel at 186,000 miles/sec in a vacuum. (speed of light) Wireless Room on board RMS Olympic, the sister ship to the Titanic. Wireless technology saves 706 lives after the Titanic sinks in 1912. http://www.evaluationengineering.com

35. Dots and Dashes are digitalVoice and Music are analog • Digital is coding a signal using a binary format, e.g. 0’s and 1’s, dots and dashes, on and off • Analog is the process of converting a signal into a wide range of continuous values.

36. Photographic picture is an analog image. www.bbc.co.uk Digital picture is a digital image – it is made up of many pixels. http://photo.net/equipment/digital/basics

37. Analog sound waves can be stored directly in their analog form but cutting grooves on vinyl. http://www.optics.rochester.edu http://jvsc.jst.go.jp

38. Transmission of Voice Edison’s Phonograph and Telephone technologies were also applied to wireless telegraph technology to create the transmission of voice and music. Without wires - This is radio. Using wires - this is what we typically think of as basic telephone technology.

39. Edison’s Other Inventions The Phonograph in 1877 used telephone technology to record sounds on a wax cylinder. The first voice recorder Smithsonian

40. birminghamstories.co.uk http://www.nps.gov

41. Record Needle - Stylus Contacts the recorded disc and transfers its vibrations to the rest of the system As the stylus rides along the walls of the moving groove, it vibrates back and forth with each ripple in a wall. Two transducers attached to this stylus sense its motions and produce electric currents that are related to those motions. The two most common transduction techniques are electromagnetic (a coil of wire and a magnet move relative to one another as the stylus moves and this causes current to flow through the coil) Transducer: converts input energy of one form into output energy of another. http://www.answers.com Louis A. Bloomfield

42. Electromagnets used in Tape Players too The electromagnet consists of an iron core wrapped with wire, as shown in the figure. During recording, the audio signal is sent through the coil of wire to create a magnetic field in the core. This flux is what magnetizes the oxide on the tape. During playback, the motion of the tape pulls a varying magnetic field across the gap. This creates a varying magnetic field in the core and therefore a signal in the coil. A – Tape HowStuffWorks

43. Wireless transmission of Analog Data(“Listening to the Radio”) • Transmitting dots and dashes (digital) required a human computer to decode the message. • Sending Morse codes was slow

44. First radio broadcast of audio on Christmas Eve in 1906 Reginald Fessenden, Canadian Fessended commemorates this event by playing “O Holy Night” on the Violin

45. First radio stations in the US • WWJ in Detroit • KDKA in Pittsburg • In 1920, the results of the presidential election were broadcasted. • “San Jose Calling” was the world's first radio station with scheduled programming in 1910 (now known as KCBS)

46. Turned into a Electromagnetic Wave Transmission This is Amplitude Modulation (AM) Carrier Wave’s amplitude is modulated Amplitude is volume and frequency is the pitch. Audible range: 20 Hz - 20 kHz Audio http://www.answers.com

47. Turned into a Electromagnetic Wave This is Frequency Modulation (FM). This requires greater bandwidth but it is easier to cancel out noise.

48. Electromagnetic Spectrum http://www.lbl.gov/MicroWorlds/ALSTool/EMSpec/EMSpec2.html

49. AM Band - 520-1700 kHz • FM Band - 87.5 to 108.0 MHz • Stations west of the Mississippi start with a K; east of the river stations begin with W