1. Data Communications Ⅰ Yu-Ping Lin Edit 652 Distance Learning Applications

2. What is data communications?  Definition  Three Elements A Sending Unit A Transmission Channel A Receiving Unit

3. Three Elements

4. Why data communications?  Data Capture at the Information Source  Rapid Dissemination of information  Improved management and centralized control of business data

5. District1 District2 District3 Central Office

6. District1 District2

7. Central Computer Mini compute r

8. Data Communications Applications  Remote Job Entry A batch-processing application (Figure 9-2) Often employed in computer programming course

10. Data Communications Applications  On-Line Inquiry Often used to check the credit-card purchase Airline Reservations System ─ SABRE http://www.sabre-holdings.com/index.html

11. Data Communications Applications  Computer-to-Computer Networks Distributed computers are linked together (Figure 9-4 ) The precursor of the Internet ─ ARPANET

13. Reference Mary Sumner. Computers Concepts and Uses