Chapter VI Data Communication: Delivering Information Anywhere and Anytime By: AP CHEN P. JOVER BSIT - III

Defining Data Communication Data communication is the electronic transfer of data from one location to another. An information system’s effectiveness is measured in part by how efficiently it delivers information, and data communication system is what enables an information system to carry out this function.

Why Managers Need to Know About Data Communication ◦ Data communication has become so interwoven into fabric of corporate activity that separating an organization’s core function from the data communication systems that enable and support them is difficult. It can enhance decision makers’ efficiency and effectiveness in many ways. For example, they support just-in-time delivery of goods, which reduces inventory cost and improves competitive edge. It also enable organizations to use and electronic file transfer to improve efficiency and productivity.

How data communication technologies are used in the workplace: Employees can get training online, through virtual classrooms using data communication technologies. Internet searches for information on products, services, and innovation immediately. The Internet and data communication systems facilitate lifelong learning, which will be an asset for knowledge workers of the future. Boundaries between work and personal life are less clear-cut, as data communication is more available in both homes and business. Improved data communication technologies make Web and video conferencing easier, which can reduce the cost of business travel.

Managers need a clear understanding of the following concepts in data communication: The basic of data communication and networking The internet, intranets and extranets Wired and wireless networks Network Security issues and measures Organozational and social effects of data communication Globalization Issues Application of data communication

Words to note: Bandwidth is the amount of data that can be transferred from one point to another in a certain period of time. Attenuation is the loss of power in a signal as it travels from the sending device to the receiving device. Broadband data transmission multiple pieces of data are sent simultaneously to increase the transmission rate. Narrowband Is a voice-grade transmission channel capable of transmitting a maximum of 56,000 bps. Protocols are rules that govern data communication.

Basic Components of Data Communication System Sender and Receiver Devices -An input/output device, or a “thin client,” is used only for sending or receiving information and has no processing power. -An intelligent terminal, a workstation, or a personal computer servers as an input/output devices or as a stand-alone system. Modems -A modem (“modulator-demodulator”) is a device that connects a user to the Internet. Not all Internet connection requires a modem; for example, wireless uses connection via access point, and and satellite users use a satellite dish. Digital subscriber line (DSL) a common carrier service, is a high-speed service that uses ordinary phone lines. Communication Media Communication media, or channels, connects sender and receiver devices. It can be conducted ( wired or guided) or radiated (wireless). Conducted Media provide a physical path along which signals are transmitted and include twisted-pair cable, coaxial cable, and fiber optics. Radiated media use an antenna for transmitting data through air or water. It can be point-to-point or a multi point system.

Processing Configurations Centralized Processing  In a centralize processing system, all processing is done at one central computer. The main advantage of this configuration is being able to excersice tight control on system operation and application. Decentralization Processing  In Decentralization Processing, each user, department or division has its own computer for performing processing task. It is more certainly more responsive to user than centralized processing unit.

Distributed Processing -Distributed Processing maintains centralized control and decentralizes operation. Processing power is distributed among several location. The Advantages of Distributed Processing:  Accessing unused processing power is possible  Modular design means computer power can be added or removed, based on need.  Distance and location aren’t limiting  It is more compatible with organizational growth  Fault tolerance is improved because of availability of redundant resources.  Resources, such high-quality laser printers, can be shared to reduce costs.  Reliability is improved because system failures can be limited to only one site.  The system is more responsive to user.

Open Systems Interconnection Model The Open Systems Interconnection (OSI) model is a seven layer architecture for defining how data is transmitted from computer to computer in a network, from the physical connection to the network to applications users run. OSI Architecture Layers:  Application Layer serves as the window through which application access network services.  Presentation Layer responsible for formatting messages packets.  Session Layer Establishes communication session between computers  Transport Layer generates the receiver’s address and ensures packets are delivered without error, in sequence and with no loss or duplication.  Network Layer Responsible for routing.  Data Link Layer Oversees establishing and controlling the communication link.  Physical Layer Electrical Connection between computers and the transmission medium and defines the physical medium used for communications.

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