Presentation on theme: "History of Telecommunications (Chapter 1) ENGR 475 – Telecommunications Harding University August 22, 2006 Jonathan White."— Presentation transcript:
History of Telecommunications (Chapter 1) ENGR 475 – Telecommunications Harding University August 22, 2006 Jonathan White
Outline What is Telecommunications? The time before phones Who actually invented the telephone? 1900 – 1982 – Regulated AT & T Monopoly 1982 – Long Distance Competition 1996 – Local dial tone competition 2000 and Beyond – WWW, internet phones
Telecomm. Definition Transmission of signals over a distance for the purpose of communication. –The word telecommunication is adapted from a French word. It is a compound of the Greek prefix tele, meaning 'far off', and communication, meaning 'to transfer information'. 3 parts: –Transmitter –Medium –Receiver
Telecomm. Definition What are some examples of Telecommunication systems? –Name the mediums for each.
Time before Phones 1831 – Professor Joseph Henry, Albany, NY – Ring a bell at a distance by connecting and disconnecting wires. May 24, Samuel Morse sends from Baltimore to Washington, D.C. “What hath God wrought.” –Numbers 22:23 –Morse code
Time before Phones 1854 – 25,000 miles of telegraph wires have been laid across the US. –Train schedules, weather, important news 1864 – A telegraph line spans the entire continental US –Western Union is formed – Trans Atlantic telegraph –8 words a minute Very costly
Who invented the Phone? 1861 – Johann Reiss, a German physics teacher, completed an almost working version of a telephone. –Used: sausage skin, beer barrel, platinum bar –Function: sent musical notes to a receiver that could play them. –Downsides: same idea as the telegraph; making and breaking a circuit. Not continuous.
Who invented the Phone? 1871 – Antonio Meucci, an Italian immigrant living in New York, files a caveat (an announcement of invention) of a talking telegraph. However, due to financial hardships, he is unable to pay for a full patent when the caveat is due 3 months later. –Had a working prototype. –Honored in 2002 by Congress.
Who invented the Phone? February 14, 1876 (Valentine’s Day), Boston, MA – US Patent Office –9:30 AM – Elisha Gray (or his lawyer) files a caveat for an invention described as “the art of transmitting vocal sounds or conversations telegraphically through an electric circuit.” –11:30 AM – Alexander Graham Bell’s lawyer files AND pays for a patent described as "Improvements in Telegraphy.“ –2:30 PM – Elisha Gray’s caveat is paid for so that a patent can be granted.
Who invented the Phone? Alexander Graham Bell (1867) Elisha Gray (1878)
Who invented the Phone? US Patent 174,465 –Said to be the most valuable patent ever Over 600 lawsuits were filed in the 1800’s over it. Awarded to: –Bell in 1876 Bell tried to sell the patent rights to Western Union in 1876 for $100,000. Western Union said the patent was worthless; who’d want voice when the telegraph still work?
Who invented the Phone? More about Alexander Graham Bell: –Wife was deaf. –Wanted to communicate to her at a distance. –1874 – phonoautograh made out of a dead man’s ear. Ear’s membrane vibrated differently based on the intensity of the sound. Used to switch a lever on and off and “write”. He thought that by using a membrane to convert sounds of varying intensity into electrical current of varying intensity and then reversing the process on the other end with another membrane, he could replicate speech over long distances.
Who invented the Phone? Bell’s first phone used a metal disk attached to a rod floating in acid to create a variable resistance. –A change in intensity made the disk vibrate differently – Thomas Edison invents the carbon microphone. –Used in phones until late 1970’s A phone produced from around 1900 on will still work on today’s phone network.
Who invented the Phone? When the patents were filed, Bell’s phone didn’t work. –Gray’s was a better design March 10, 1876: –“ Mr. Watson, Come here! I want you!” –First telephone message. A one wire, copper system was used at first. A 2 wire system was invented in Much clearer conversation. - Insulated by cotton/rubber and twisted
Who invented the Phone? Alexander Graham Bell was awarded the first US patent for a device which ultimately became the telephone. Who invented the telephone is very debatable.
– Bell telephone company formed – Western Union forms the American Speaking Telephone Company using Gray’s invention. –All phones are party lines initially – In July, a druggist in New Hartford, Connecticut invents the switchboard.
Ringers: –Thumper (pre switchboard) –1878: Thomas Watson invents the ‘Magneto’ An AC current sent down the line that would make a hammer move back and forth between 2 bells. –The first non-voice signal that the telephone system used.
– An undertaker named Almon Strowger in Kansas City, Missouri invents the first phone that uses a keypad –Also uses automatic connections from the central office using electromagnetic rods. Automatic switching didn’t take hold, however. –1921 – first automatic system installed in Omaha, Nebraska. –It wasn’t until after well after WW 2 that automatic systems were the norm. Think of the Andy Griffith Show.
– Because of the measles epidemic in Massachusetts, a doctor recommends numbering phone lines instead of using names. –The system was eventually expanded to a 2 letter, 5 number system –The first 2 letters identified the state / CO. –The next number identified the CO. –The last 4 numbers identified the customer. PE –This system was used until the 1950’s and beyond.
– Invention of the rotary dial phone. –Less wiring and cheaper.
1900 – 1982 Monopoly 1899 – American Bell is acquired/renamed AT & T – American Telephone and Telegraph. Many companies entered the phone market around this time. –None were interconnected. –You had to have the same carrier. –You had to buy your phone from your provider and they owned the network. –AT & T eventually become a natural monopoly by the 1920’s for long distance calls. This was allowed by law. –No competition and expensive.
1900 – 1982 Monopoly January 8, 1982 – AT & T is broken up: –AT & T was broken up into 23 Bell Operating Companies, that would compete against AT & T in the telephone long distance market. –AT & T had to let other companies use their network. –AT & T would only be in the long distance market Very Bad. –AT & T was bought by one of its children (SBC) in 2005.
1996 – Telecommunications Act February 1996 – –There can now be competition in the local market. –The telephone industry was deregulated. –You can now get local, long distance, cellular, high speed Internet, and digital cable all from one provider, all over the same network. Prices go way down. Who owns the Internet? Who owns the telephone network? Are they even separate networks? –Circuit switched vs. packet switched. –QOS
2000 and Beyond The telephone network is now all digital, up to the end user’s home (local loop). –Some are digital – DSL. –Most are analog phones. Is telephony going to become just another application of the Internet? –Maybe Many applications exist that we haven’t talked about: –Caller ID (1991), 911 emergency service (1968),cellular phones (1984)