2. Slide 4-1 Chapter 4 Terms Data Communications and Networking Considerations Introduction to Information Systems Judith C. Simon

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4. Slide 4-3 Chapter 4 Terms Review ä Analog signal: a continuous signal a continuous signal ä Asynchronous communications: one-character-at-a-time transmission of data one-character-at-a-time transmission of data ä Bandwidth: the range (highest minus lowest) of frequencies that can be transmitted ä Baud rate: how fast signals can by sent over a communications channel

5. Slide 4-4 Chapter 4 Terms Review ä Bits per second (bps): how fast data can be sent over a communications channel; bps may be greater than the baud rate how fast data can be sent over a communications channel; bps may be greater than the baud rate ä Bridge: hardware that connects two homogeneous (similar) networks hardware that connects two homogeneous (similar) networks ä Client/server model: a system that includes at least one server—a computer that provides a service to at least one other computer (a client); often referred to as a distributed system a system that includes at least one server—a computer that provides a service to at least one other computer (a client); often referred to as a distributed system

6. Slide 4-5 Chapter 4 Terms Review ä Codec: device that converts analog video and audio data into digital signals device that converts analog video and audio data into digital signals ä Common carrier: an organization that provides a common type of communications service to many people, such as telephone service an organization that provides a common type of communications service to many people, such as telephone service ä Data communications: use of a computer-based system to transmit data electronically use of a computer-based system to transmit data electronically

7. Slide 4-6 Chapter 4 Terms Review ä Data communications media: means of transmitting data such as wire pairs, coaxial cables, or microwave means of transmitting data such as wire pairs, coaxial cables, or microwave ä Dedicated communications channel: service in which the connection from one piece of hardware to another is used only for that connection service in which the connection from one piece of hardware to another is used only for that connection ä Digital signal: a discrete or pulse-type signal

8. Slide 4-7 Chapter 4 Terms Review ä Full duplex: a communications channel over which data transmissions can travel in both directions simultaneously a communications channel over which data transmissions can travel in both directions simultaneously ä Gateway: hardware that connects heterogeneous (not similar) networks hardware that connects heterogeneous (not similar) networks ä Half duplex: a communications channel over which data transmissions can travel in both directions, but not at the same time a communications channel over which data transmissions can travel in both directions, but not at the same time

9. Slide 4-8 Chapter 4 Terms Review ä Latency: amount of time required to get data from one point to another amount of time required to get data from one point to another ä Local area networks (LAN): computers linked into a network in a small geographic area and widely used for sharing data, software, and hardware computers linked into a network in a small geographic area and widely used for sharing data, software, and hardware ä Medium: the means by which a transmission occurs, also referred to as a channel; examples include wire pairs, coaxial cables, optical fiber, and microwave the means by which a transmission occurs, also referred to as a channel; examples include wire pairs, coaxial cables, optical fiber, and microwave

10. Slide 4-9 Chapter 4 Terms Review ä Message: a group of bits being transmitted a group of bits being transmitted ä Middleware: software that links client and server applications in distributed systems software that links client and server applications in distributed systems ä Modem: device that converts digital data to analog (modulation) and analog data to digital (demodulation) device that converts digital data to analog (modulation) and analog data to digital (demodulation)

11. Slide 4-10 Chapter 4 Terms Review ä Network: a group of computers and other hardware that is connected by communications media so that resources can be shared a group of computers and other hardware that is connected by communications media so that resources can be shared ä Network protocol: rules for network communications; examples include CSMA/CD, token passing and TCP/IP rules for network communications; examples include CSMA/CD, token passing and TCP/IP ä Packet-switched service: a type of communications service in which messages travel in small groupings (packets) and may be relayed through several computers before arriving at the destination a type of communications service in which messages travel in small groupings (packets) and may be relayed through several computers before arriving at the destination

12. Slide 4-11 Chapter 4 Terms Review ä Parallel communications: use of multiple paths at one time to transmit bits of data use of multiple paths at one time to transmit bits of data ä Receiver: the recipient of data being communicated the recipient of data being communicated ä Router: device that selects the channel (route) to use for transmission of a message device that selects the channel (route) to use for transmission of a message ä Sender the originator of a message being communicated

13. Slide 4-12 Chapter 4 Terms Review ä Serial communications: use of one path to transmit bits of data use of one path to transmit bits of data ä Simplex: a communications channel over which data transmission travels in one direction only a communications channel over which data transmission travels in one direction only ä Synchronous communications: transmission of a block of characters at a time rather than one character at a time

14. Slide 4-13 Chapter 4 Terms Review ä Telecommunications: any communications over long distances, including those by telephone or telegraph as well as by computer ä Topology: method of connecting computers in a network; examples include fully interconnected, chain, loop, star, ring, and bus

15. Slide 4-14 Chapter 4 Terms Review ä Value-added carrier: organization that enhances the services of common carriers (an added value) and sells the use of this capability ä Wide area network (WAN): computers linked into a network in a large geographic are and widely used for sharing data, software and hardware

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