2. Effective communications are essential to organizational success
Define the terms communications and telecommunications and describe the components of a telecommunications system
Principles of Information Systems, Seventh Edition

3. An unmistakable trend of communications technology is that more people are able to send and receive all forms of information over greater distances at a faster rate
Identify broad categories of communications media and discuss the basic characteristics of specific media types
Describe how a modem works
Explain the types of telecommunications carriers today and the services they provide
Principles of Information Systems, Seventh Edition

4. Identify the benefits associated with a telecommunications network
Define the term network topology and identify five alternatives
Discuss the different communications protocols and devices used for telecommunications
Name three distributed processing alternatives and discuss their basic features
List some telecommunications applications that organizations are benefiting from today
Principles of Information Systems, Seventh Edition

5. An Overview Of Communications Systems
Communications: the transmission of a signal by way of a medium from a sender to a receiver
Signal contains a message composed of data and information
In telecommunications, sender transmits a signal through a transmission medium such as a cable
Principles of Information Systems, Seventh Edition

6. Figure 6.2: Communications and Telecommunications
Principles of Information Systems, Seventh Edition

7. An Overview Of Communications Systems (continued)
Communications can be synchronous or asynchronous
Synchronous communications: the receiver gets the message instantaneously
Asynchronous communications: the receiver gets the message some period of time after it is sent
Principles of Information Systems, Seventh Edition

8. Telecommunications
Telecommunications: electronic transmission of signals for communications, via telephone, radio, television, etc.
Data communications: subset of telecommunications that refers to the electronic collection, processing, and distribution of data, typically between computer system hardware devices
Telecommunications medium: anything that carries an electronic signal and interfaces between a sending device and a receiving device
Principles of Information Systems, Seventh Edition

9. Figure 6.3: Elements of a Telecommunications System
Principles of Information Systems, Seventh Edition

10. Communications Channels: Basic Communications Channel Characteristics
Communication channels can be classified as simplex, half-duplex, or full-duplex
Simplex channel: can transmit data in only one direction
Half-duplex channel: can transmit data in either direction, but not simultaneously
Full-duplex channel: permits data transmission in both directions at the same time
Principles of Information Systems, Seventh Edition

11. Channel Bandwidth and Information-Carrying Capacity
Bandwidth: the range of frequencies that an electronic signal occupies on a given transmission medium
Shannon’s fundamental law of information theory: states that the information-carrying capacity of a channel is directly proportional to its bandwidth
Broadband: telecommunications in which a wide band of frequencies is available to transmit information
Principles of Information Systems, Seventh Edition

12. Types of Media
Guided transmission media: communications signals are guided along a solid medium
Wireless media: communications signals are sent over airwaves
Principles of Information Systems, Seventh Edition

13. Table 6.1: Transmission Media Types
Principles of Information Systems, Seventh Edition

14. Table 6.1: Transmission Media Types (continued)
Principles of Information Systems, Seventh Edition

15. Modems
A typical telephone line can only accommodate an analog signal (a continuous, curving signal)
A computer generates a digital signal representing bits
Modem: a device that translates data from digital to analog and analog to digital
Principles of Information Systems, Seventh Edition

16. Figure 6.8: How a Modem Works
Principles of Information Systems, Seventh Edition

17. Multiplexers
Multiplexers: devices that allow several telecommunications signals to be transmitted over a single communications medium at the same time
Principles of Information Systems, Seventh Edition

18. Figure 6.9: Use of a Multiplexer to Consolidate Data Communications onto a Single Communications Link
Principles of Information Systems, Seventh Edition

19. Front-End Processors
Front-end processors: special-purpose computers that manage communications to and from a computer system
Connect a midrange or mainframe computer to hundreds or thousands of communications lines
Principles of Information Systems, Seventh Edition

20. Figure 6.10: Front-End Processor
Principles of Information Systems, Seventh Edition

21. Carriers and Services
Local exchange carrier (LEC): a public telephone company in the United States that provides service to homes and businesses within its defined geographical area
Competitive local exchange carrier (CLEC): a company that is allowed to compete with the LECs, such as a wireless, satellite, or cable service provider
Long-distance carrier: a traditional long-distance phone provider, such as AT&T, Sprint, or MCI
Principles of Information Systems, Seventh Edition

22. Switched and Dedicated Lines
Switched line: a communications line that uses switching equipment to allow one transmission device to be connected to other transmission devices
Dedicated line: a communications line that provides a constant connection between two points; also called a leased line
Principles of Information Systems, Seventh Edition

23. Voice and Data Convergence
Voice over Internet protocol (VoIP): the basic transport of voice in the form of a data packet using the Internet protocol
IP telephony is the technology for transmitting voice communications over a network using an open standards- based Internet protocol
Voice and data convergence: the integration of voice and data applications in a common environment
Principles of Information Systems, Seventh Edition

24. WATS
Wide-area telephone service (WATS): a fixed-rate long- distance telecommunications service for heavy users of voice services
IN-WATS service
OUT-WATS service
Principles of Information Systems, Seventh Edition

25. ISDN
Integrated services digital network (ISDN): a set of standards for integrating voice and data communications onto a single line via digital transmission over copper wire or other media
ISDN requires special adapters at both ends of the transmission line
ISDN Basic Rate Interface
ISDN Primary Rate Interface
Principles of Information Systems, Seventh Edition

26. Figure 6.12: ISDN Network Switching
Principles of Information Systems, Seventh Edition

27. T-Carrier System
Introduced in the 1960s to support digitized voice transmission
Uses four wires and provides duplex capability
T-1 carrier is capable of carrying Mbps over copper wire; commonly used in U.S., Japan, and Canada
T-3 line is capable of transmitting data at a rate of Mbps
Principles of Information Systems, Seventh Edition

28. Digital Subscriber Line (DSL)
Digital subscriber line (DSL): a telecommunications technology that delivers high-bandwidth information to homes and small businesses over ordinary copper telephone wires
Provides a transmission rate of 512 Kbps to Mbps from the central office to the subscriber
Provides a transmission rate of about 128 Kbps from the subscriber to the central office
Can carry both data and voice signals
Principles of Information Systems, Seventh Edition

29. Wireless Mobile Table 6.3: Some Wireless Data Communications Options
Principles of Information Systems, Seventh Edition

30. Networks
Computer network: the communications media, devices, and software needed to connect two or more computer systems and/or devices
Network nodes: the computers and devices on the networks
Principles of Information Systems, Seventh Edition

31. Network Types Personal area network (PAN) Local area network (LAN)
Metropolitan area network (MAN)
Wide area network (WAN)
International network
Principles of Information Systems, Seventh Edition

32. Network Topology
Network topology: logical model that describes how networks are structured or configured
Principles of Information Systems, Seventh Edition

33. Figure 6.15: The Basic Network Topologies
Principles of Information Systems, Seventh Edition

34. Terminal-to-Host, File Server, and Client/Server Systems
Classifications based on how computers on the network connect and interoperate
Terminal-to-host: application and database reside on one host computer, and the user interacts with application and data using a “dumb” terminal
File server: the application and database reside on one host computer (file server)
Client/server: multiple computer platforms are dedicated to special functions such as database management, printing, communications, and program execution
Principles of Information Systems, Seventh Edition

35. Figure 6.18: Client/Server Connection
Principles of Information Systems, Seventh Edition

36. Interconnecting Networks: Communications Protocols
Open Systems Interconnection (OSI) model
Transmission Control Protocol/Internet Protocol (TCP/IP)
Systems Network Architecture (SNA)
IEEE (Ethernet)
Principles of Information Systems, Seventh Edition

37. Communications Protocols (continued)
Frame Relay
Asynchronous Transfer Mode (ATM)
FireWire
Principles of Information Systems, Seventh Edition

38. Wireless Communications Protocols
Bluetooth
IEEE b (Wi-Fi)
IEEE g
IEEE (WiMax)
IEEE (MBWA)
Principles of Information Systems, Seventh Edition

39. Wireless Communications Protocols (continued)1G 2G
2.5G 3G
Multichannel Multipoint Distribution System (MMDS)
Principles of Information Systems, Seventh Edition

40. Network Switching Devices
Private branch exchange (PBX): an on-premise switching system owned or leased by a private enterprise that interconnects its telephones and provides access to the public telephone system
Bridge: a device used to connect two or more networks that use the same communications protocol
Switch: a telecommunications device that routes incoming data from any one of many ports to a specific output port that will take the data toward its intended destination
Principles of Information Systems, Seventh Edition

41. Network Switching Devices (continued)
Router: a device or software in a computer that determines the next network point to which a data packet should be forwarded toward its destination
Hub: a place of convergence where data arrives from one or more directions and is forwarded out in one or more other directions
Gateway: a network point that acts as an entrance to another network
Principles of Information Systems, Seventh Edition

42. Network Basics: Basic Processing Strategies
Centralized processing: all processing occurs in a single location or facility
Decentralized processing: processing devices are placed at various remote locations
Distributed processing: computers are placed at remote locations but connected to each other via a network
Principles of Information Systems, Seventh Edition

43. Communications Software
Network operating system (NOS): systems software that controls the computer systems and devices on a network and allows them to communicate with each other
Network-management software: enables a manager on a networked desktop to monitor the use of individual computers and shared hardware, scan for viruses, and ensure compliance with software licenses
Principles of Information Systems, Seventh Edition

44. Telecommunications Applications
Linking personal computers to mainframes and networks
Voice mail
Electronic software distribution
Electronic document distribution
Principles of Information Systems, Seventh Edition

45. Telecommunications Applications (continued)
Call centers
Telecommuting
Videoconferencing
Electronic data interchange (EDI)
Principles of Information Systems, Seventh Edition

46. Telecommunications Applications (continued)
Public network services
Electronic funds transfer (EFT)
Distance learning
Specialized systems and services
Principles of Information Systems, Seventh Edition

47. Summary
Communications: the transmission of a signal by way of a medium from a sender to a receiver
In telecommunications, the sender transmits a signal through a transmission medium such as a cable
Transmission media types: twisted-pair wire cable, coaxial cable, fiber-optic cable, microwave, cellular, and infrared
Telecommunications carriers can be divided into local exchange carriers, competitive local exchange carriers, and long-distance carriers
Principles of Information Systems, Seventh Edition

48. Summary (continued)
A computer network consists of the communications media, devices, and software needed to connect two or more computer systems and/or devices
Network types: personal area network (PAN), local area network (LAN), metropolitan area network (MAN), wide area network (WAN), and international network
Network topologies: ring, bus, hierarchical, star, and hybrid
Options for how computers on a network connect: terminal-to-host, file server, and client/server
Principles of Information Systems, Seventh Edition

49. Summary (continued)
Communications protocols include the Open Systems Interconnection (OSI) model, Transmission Control Protocol/Internet Protocol (TCP/IP), IEEE (Ethernet), etc.
Network switching devices: private branch exchange (PBX), bridge, switch, router, hub, and gateway
Examples of telecommunications applications are voice mail, electronic software distribution, telecommuting, videoconferencing, electronic funds transfer, and distance learning
Principles of Information Systems, Seventh Edition