1. CIS 103 — Applied Computer Technology Last Edited: September 17, 2010 by C.Herbert Personal Computer Data Communications

2. Digital Data Data in a computer is stored as a series of bits, or binary digits. Each bit is a one or a zero, represented in a computer by electrical, magnetic and optical technology. CIS 103 Applied Computer TechnologyData Communications 2

3. Digital Data Every object in a computer’s memory is stored as a series of bits. CIS 103 Applied Computer TechnologyData Communications 3 Numbers

4. Digital Data Every object in a computer’s memory is stored as a series of bits. CIS 103 Applied Computer TechnologyData Communications 4 Text

5. Digital Data Every object in a computer’s memory is stored as a series of bits. CIS 103 Applied Computer TechnologyData Communications 5 Pictures

6. Digital Data Every object in a computer’s memory is stored as a series of bits. CIS 103 Applied Computer TechnologyData Communications 6 Sound

7. Digital Data Every object in a computer’s memory is stored as a series of bits. CIS 103 Applied Computer TechnologyData Communications 7 Video

8. … every object is stored as a series of bits. Digital Data 01000001 01000010 01000011 01000100 01000101 01000110 01000111 01001000

9. CIS 103 Applied Computer TechnologyData Communications 9 Bits can be moved in groups over several parallel wires at the same time. or one at a time over a single wire … Data Communications 9 01000001 01000010 01000010 01000001 Serial Communication Parallel Communication Parallel and Serial Communication

10. Data Communications 10 Parallel communication uses a set of wires called a data bus, so it is: faster more expensive often used for short distances (inside a computer) 01000010 01000001 Data Bus The size of the data bus affects a computer’s word length. An 8-bit word Serial and Parallel Communication

11. CIS 103 Applied Computer TechnologyData Communications 11 Serial communication: is not as fast is less expensive is often used for long distances (between computers) requires only one data wire often uses two data wires– one in each direction 01000001 01000010 Serial Communication Serial and Parallel Communication

12. Data Communication Standards a communications protocol defines: the electronic signals to be used how fast the data should be sent error checking methods and other technical details CIS 103 Applied Computer TechnologyData Communications 12

13. Data Communication Standards A data communication standard includes: a communications protocol the type of connectors to be used the type cables to be used CIS 103 Applied Computer TechnologyData Communications 13

14. Data Communication Standards Several agencies and associations maintain data communications protocols and standards: International Telecommunications Union (ITU) – a technical committee sponsored by the United Nations Institute of Electrical and Electronics Engineers (IEEE) – a professional group Electronics Industries Association (EIA) – a trade association CIS 103 Applied Computer TechnologyData Communications 14

15. Data Communication Standards Three commonly used serial communications standards are: RS-232c USB Firewire CIS 103 Applied Computer TechnologyData Communications 15

16. RS-232c The RS-232c standard: was created by the IEA in 1969 for terminals connected to old mainframe computers Used with early personal computers and telephone modems not used as much today, but is still used with some printers and older equipment CIS 103 Applied Computer TechnologyData Communications 16

17. RS-232c There are two types of RS232c connectors 9-pin 25-pin CIS 103 Applied Computer TechnologyData Communications 17

18. USB In the 1990’s several computer companies formed a new trade association – the Universal Serial Bus Implementers Forum (USB-IF) – to develop a faster and less expensive data communication standard using newer technology. Their popular new standard is called USB (Universal Serial Bus). CIS 103 Applied Computer TechnologyData Communications 18

19. USB USB is now the most widely used data communication standard for connecting devices to personal computers. CIS 103 Applied Computer TechnologyData Communications 19

20. USB Three common versions of USB: USB USB 1.1 (1994) 12 mbps (megabits per second), cables up to 3 meters Hi-Speed USB USB 2.0 (2001) 480 mbps, 5 meters SuperSpeed USB USB 3.0 (2008) 5 gbps (gigabits per second), 5 meters CIS 103 Applied Computer Technology Data Communications 20

21. USB Connectors CIS 103 Applied Computer Technology Data Communications 21 There are six different types of USB connectors. … more about USB in the next lesson

22. Firewire first developed by Apple Computers approved as standard IEEE 1394 in 1995 Sony’s version is iLInk, Texas Instruments’ is Lynx is the High Definition Audio-Video Network Alliance (HANA) standard for the audio visual industry The automobile industry, the military, and the NASA Space Shuttle all use Firewire CIS 103 Applied Computer Technology Data Communications 22

23. Firewire Two common versions of Firewire: Firewire 400 (IEEE 1394a) has a maximum data transfer rate of 400 Mbps Firewire 800 (IEEE 1394b) is capable of 800 Mbps over standard cables and up to 3,200 Mbps using fiber optic cables CIS 103 Applied Computer Technology Data Communications 23

24. Firewire Connectors Both 6-pin and 4-pin Firewire connectors are common CIS 103 Applied Computer Technology Data Communications 24

25. Firewire vs. USB Firewire is faster and more sophisticated than USB Is capable of longer distances (up to 100 meters) the equipment is significantly more expensive It can be a little harder to use USB is far more common for connecting devices to personal computers. CIS 103 Applied Computer Technology Data Communications 25

26. Next... Connecting USB devices to a personal computer CIS 103 Applied Computer Technology Data Communications 26