Data Communications Ⅰ

Yu-Ping Lin

Edit 652 Distance Learning Applications

What is data communications?

Definition

Three Elements• A Sending Unit • A Transmission Channel • A Receiving Unit

Three Elements

Why data communications?

Data Capture at the Information Source

Rapid Dissemination of information

Improved management and centralized control of business data

District1

District2 District3

CentralOffice

District1

District2

Central Computer

Mini computer

Mini computer

Mini computer

Data Communications Applications

Remote Job Entry• A batch-processing application (Figure 9-2) • Often employed in computer programming course

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

Data Communications Applications

Computer-to-Computer Networks• Distributed computers are linked together (Figure

9-4 )

• The precursor of the Internet ─ ARPANET

Reference

Mary Sumner.

Computers Concepts and Uses