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24 Cards in this Set
- Front
- Back
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What are the 3 elements of a sine wave
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amplitude
phase frequency |
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What is a concentrator
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a device that allows several terminal data sources to share a single DATA LINK ONE AT A TIME
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What type of communication sytem would perform remote batch processing
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Time sharing
pg. 1-10 |
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In what device is the data buffer used to absorb the difference in data transfer speeds between the CPU and the telephone line
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Communications controller
PAGE 2-7 & 2-8 READ |
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WHAT IS THE FORMULA FOR CENTER FREQUENCY
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UPPER FREQUENCY + LOWER FREQUENCY/2
1100hz + 100hz/2 CENTER FREQUENCY = 600HZ |
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A modem transmits 3,000 bits per second. Each signal element represents three bits of binary information. What is the baud rate of the modem
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1000bps
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What are the Characteristics of a data communication system
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1. Direct machine-to-machine communication
2. occurs through a common link 3. involves the movement of encoded information by means of an elctrical transmission |
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What are computer-to-computer Systems
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Communication networks that allow separate computers to share common data
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What type of information can not be transmitted across telephone lines
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Digital signals
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What are the key elements of a teleprocessing network
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1. central computer
2. software 3. communications link 4. remote terminal equipment |
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Explain Store-and-Forward Message Switching Systems
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A communications systems that enable message to be transmitted in a step-by-step method using switching computers
pg. 1-8 |
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What are the classifications of communications systems
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1. Information storage and retrieval
2. Computer-to-Computer 3. Store and Forward message switching 4. time sharing |
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What are the communication channels (link)offered by telephone companies
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1. Narrow band
2. voice grade 3. wide band |
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What is real time
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An event recorded or reported at the actual time it occurs
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What is a Code System
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A system of symbols and rules representing information. That has the following characteristics:
* common to both sender and receiver *it is efficient, uses minimum energy to transmit maximum energy |
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Describe wide band channels
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a combination of a number of voice facilites and range from 5khz to 5mhz. And are often leased for business use.
pg 2-25 |
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What is a multiplexer
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permits SERVERAL terminal data sources to share a SINGLE data link at the same time
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What is an Information storage and retrieval systems
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A computer based communications system consisting of a terminal that monitors or provides information to a common database via the telephone
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Descsribe narrow-band channels
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Narrow-band facilities are used primarily for teletype communications and carry up to 75 bits per second.
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Describe voice-grade channels
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Voice grade channels are the most common communications link and have a bandwidth for voice communications. and can transmit data from 300 t0 10,000 bits per second
pg 2-25 |
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WHAT IS THE FORMULA FOR BAND WIDTH
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3000HZ (upper frequency) - 300hz (lower frequency) = 2700 HZ
bandwidth = 2700hz |
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What are the elements of a communication system
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1.message source
2. medium 3. sink |
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What are the characteristics of a Time-sharing communications systems
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1. Uses Data communication for remote acces
2. Responds immediately to a remote user's inquiry 3. Services many users at the Same time 4. A REMOTE USER can introduce new programs |
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What is a modem
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A device that impresses digital information onto a carrier frequency.
** also called a modulator/demodulator ** |
