1. Chapter 21 Electronic Communications Systems, 5 th Edition By: Wayne Tomasi

2. Introduction Data Communications. The transmission, reception, and processing of digital information. Data. Information that is stored in digital form. Information that has been processed, organized and stored. Data Communications Network. Systems of interrelated computers and computer equipment connected through the public telephone network or similar network infrastructure. Any system of computers, computer terminals, or computer peripheral equipment to transmit and/or receive information between two or more locations.

3. Network. A set of devices, nodes, or stations interconnected by media links. Internet. A public data communications network used by millions of people worldwide to exchange business and personal information. Intranet. Private data communications networks used by many companies to exchange information among employees and resources. World Wide Web (www). A server-based application that allows subscribers to access the services offered by the Web.

4. History of Datacom 1753 One of the earliest means of communicating electrically coded information through a 26 wire system. 1833 Carl Friedrich Gauss developed a system based on a 5x5 matrix representing 25 letters. 1832 The telegraph (the first data communication system) was invented by Samuel F.B. Morse. 1840 The American patent for the telegraph was granted. 1844 The first telegraph line was established between Baltimore and Washington D.C. conveying the first telegraph message “What hath God wrought!”

5. 1849 The first slow-speed telegraph printer was invented. 1850 Western Union Telegraph Company was formed in Rochester, New York, for the purpose of carrying coded messages from person to another. 1860 “High-speed” printers (15 bps) became available. 1874 Emile Baudot invented the telegraph multiplexer that allowed signals from up to six different telegraph machines to be transmitted simultaneously over a single wire. 1875 The telephone was invented by Alexander Graham Bell

6. 1899 Guglielmo Marconi succeeded in sending radio (wireless) telegraph messages. 1920 The first commercial radio stations carrying voice information were installed. 1930s Konrad Zuis, a German engineer, demonstrated a computing machine. 1940 Bell Laboratories developed the first special purpose computer using electromechanical relays for performing logical operations. 1946 The first modern-day computer (ENIAC) was developed by J. Presper Eckert and John Mauchley at the University of Pennsylvania.

7. 1949 The U.S. National Bureau of Standards developed the first all-electronic diode based computed capable of executing stored-programs. 1950s “Batch processing” computers used punched cards as an input interface, printers as an output interface, and magnetic tape reels for data storage. The first general purpose computer in the form of an automatic sequence-controlled calculator was developed jointly by Harvard University and IBM Corporation. 1951 Remington Rand Corporation built the first mass- produced electronic computer (UNIVAC).

8. 1960s Batch-processing system were replaced by on-line processing systems with terminals connected directly to the computer through serial and parallel communication lines. 1968 The landmark US Supreme Court Carterfone decision allowed non-Bell (non AT&T) equipment to be connected to the vast AT&T network. 1969 The internet began to evolve at the Advanced Research Projects Agency (ARPA) through the ARPANET. 1970s Microprocessor-controlled microcomputers were developed.

9. 1980s Personal computers became an essential item in the home and the workplace. Since then, the need to exchange digital information, and consequently, the need for data communication circuits, networks, and systems increased exponentially. 1983 AT&T agreed in a court settlement to divest itself of operating companies that provide basic local telephone service to various geographic regions of the US as a result of an anti-trust suit filed by the federal government. Mid 1980s to 1995 The United State National Science Foundation (NSF) funded a high-speed backbone called the NSFNET.

10. 1989 Tim Berners-Lee and Robert Cailliau build the prototype system which became the World Wide Web at CERN. 1991 Anders Olsson transmits solitary waves through an optical fiber with a data rate of 32 billion bits per second. 1992 Neil Papworth sends the first SMS (or text message). 1994 Internet radio broadcasting is born. 1999 45% of Australians have a mobile phone. Sirius satellite radio is introduced

11. 2001 First digital cinema transmission by satellite in Europe of a feature film by Bernard Pauchon and Philippe Binant is undertaken. 2003 Apple launches the iTunes Music Store and sells one million songs in its first week. MySpace is launched. 2004 What would become the largest social networking site in the world, Facebook is launched. 2005 Youtube, the video sharing site is launched. 2006 Twitter, microblogging is introduced.