Podcast
Questions and Answers
Data communications topologies are organized as ______, one-to-many, or many-to-many
Data communications topologies are organized as ______, one-to-many, or many-to-many
one-to-one
In data communications, there are three modes of transmission: ______, half-duplex, and duplex
In data communications, there are three modes of transmission: ______, half-duplex, and duplex
simplex
A communications channel may consist of a communications circuit, which can be either a hardware configuration or a “virtual” ______
A communications channel may consist of a communications circuit, which can be either a hardware configuration or a “virtual” ______
circuit
In data communications, there are three modes of transmission: simplex, ______, and duplex
In data communications, there are three modes of transmission: simplex, ______, and duplex
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In any communication there must be a source and one or more ______
In any communication there must be a source and one or more ______
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Members of a network may have defined relationships: they may have no ranking or they may be ______
Members of a network may have defined relationships: they may have no ranking or they may be ______
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Data communications topologies are organized as one-to-one, ______, or many-to-many
Data communications topologies are organized as one-to-one, ______, or many-to-many
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In data communications, the media we use are: electrical conductors, light pipes, and electromagnetic ______
In data communications, the media we use are: electrical conductors, light pipes, and electromagnetic ______
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The purpose of communication is to transmit data from the source to the ______
The purpose of communication is to transmit data from the source to the ______
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A portion of this chapter —the discussion of data organization sometimes called a ______ —is almost a technical history in itself
A portion of this chapter —the discussion of data organization sometimes called a ______ —is almost a technical history in itself
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The ARQ method will not receive an ______ because the circuit is unidirectional
The ARQ method will not receive an ______ because the circuit is unidirectional
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FEC requires that the communications network’s pattern of errors be analyzed and an ______ be designed to fit the identified error patterns
FEC requires that the communications network’s pattern of errors be analyzed and an ______ be designed to fit the identified error patterns
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The protocol is to ______ hands when you are introduced to someone in the United States
The protocol is to ______ hands when you are introduced to someone in the United States
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Humans are effectively ______—they typically cannot talk and listen very well at the same time
Humans are effectively ______—they typically cannot talk and listen very well at the same time
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Asynchronous generally means that something may occur at any time and its occurrence is not tied to any other ______
Asynchronous generally means that something may occur at any time and its occurrence is not tied to any other ______
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Baud rate is the line modulation rate; that is, the number of signal changes per second that are placed on the communication medium in a given ______
Baud rate is the line modulation rate; that is, the number of signal changes per second that are placed on the communication medium in a given ______
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Two framing characters were added at the start of the data block and one framing character was added at the end of the data block. An 84th character, called the block parity character, was added to the end of the transmitted block. To determine if parity was met for all the characters in the block, parity was determined horizontally for the Parity row by counting the 1s in the 83 counted columns and the result was compared to the vertical parity bit for the block parity character. Error Correction In addition to having bits devoted to assisting with error detection, what means could be used to correct an error, once one was detected. The answer is normally an automatic retransmission query, known as an _____________.
Two framing characters were added at the start of the data block and one framing character was added at the end of the data block. An 84th character, called the block parity character, was added to the end of the transmitted block. To determine if parity was met for all the characters in the block, parity was determined horizontally for the Parity row by counting the 1s in the 83 counted columns and the result was compared to the vertical parity bit for the block parity character. Error Correction In addition to having bits devoted to assisting with error detection, what means could be used to correct an error, once one was detected. The answer is normally an automatic retransmission query, known as an _____________.
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All data communications efforts involve ______ of one kind or another
All data communications efforts involve ______ of one kind or another
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Any time data is placed on a medium (magnetic or optical rotating media, and fiber cable), there is a probability of error; thus, an error detection scheme must be used. Most modern devices use a far more efficient scheme of error detection than parity checking. Though ASCII was designed for a vertical and horizontal blockchecking code, it can also be used with a cyclic redundancy check scheme that creates a check character. A CRC character is the number 8-bit check character developed by the CRC. A cyclic code divides the text bits with a binary polynomial, resulting in a check character. Checksum Any of a number of error-detection codes may be called a checksum. Many times the CRC-16 or CRC-CCITT is called a checksum; however, they are actually cyclic codes, whereas a checksum was originally designed as a linear code. The efficiency of a checksum in detecting errors is not as high as with a cyclic code, yet the circuitry to produce the checksum is less complex. Some of these codes are cyclic, some are linear, some are quasi-cyclic, and some are _____________.
Any time data is placed on a medium (magnetic or optical rotating media, and fiber cable), there is a probability of error; thus, an error detection scheme must be used. Most modern devices use a far more efficient scheme of error detection than parity checking. Though ASCII was designed for a vertical and horizontal blockchecking code, it can also be used with a cyclic redundancy check scheme that creates a check character. A CRC character is the number 8-bit check character developed by the CRC. A cyclic code divides the text bits with a binary polynomial, resulting in a check character. Checksum Any of a number of error-detection codes may be called a checksum. Many times the CRC-16 or CRC-CCITT is called a checksum; however, they are actually cyclic codes, whereas a checksum was originally designed as a linear code. The efficiency of a checksum in detecting errors is not as high as with a cyclic code, yet the circuitry to produce the checksum is less complex. Some of these codes are cyclic, some are linear, some are quasi-cyclic, and some are _____________.
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The IBM Bi-Sync protocol is ______; control depends on certain character combinations, rather than on bit patterns
The IBM Bi-Sync protocol is ______; control depends on certain character combinations, rather than on bit patterns
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Forward Error Correction Although the ARQ method of error correction discussed above detects an error and then retransmits the portion of the message that was in error, what happens when there is simplex ___________.
Forward Error Correction Although the ARQ method of error correction discussed above detects an error and then retransmits the portion of the message that was in error, what happens when there is simplex ___________.
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The protocol only allows the frame to have this pattern at its start and ______
The protocol only allows the frame to have this pattern at its start and ______
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The bit-oriented protocols do not depend on the data stream ______; they operate independently
The bit-oriented protocols do not depend on the data stream ______; they operate independently
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Framing the data usually means having some form of start ______
Framing the data usually means having some form of start ______
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The first data transmission code devoted more overhead to the error-detection scheme than to the ______ transmitted
The first data transmission code devoted more overhead to the error-detection scheme than to the ______ transmitted
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The circuit that provided this mode of operation was originally called ______
The circuit that provided this mode of operation was originally called ______
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Unidirectional is a more appropriate name for this mode of ______
Unidirectional is a more appropriate name for this mode of ______
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Half-duplex communication functions much like meaningful human ______ does
Half-duplex communication functions much like meaningful human ______ does
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In duplex mode, communication can travel in both ______ simultaneously
In duplex mode, communication can travel in both ______ simultaneously
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A digital signal is defined as one with defined discrete ______
A digital signal is defined as one with defined discrete ______
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Binary digital signals have only two ______
Binary digital signals have only two ______
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One of the bit patterns to be organized has to represent ______
One of the bit patterns to be organized has to represent ______
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American Standard Code for Information Interchange is an example of a text ______
American Standard Code for Information Interchange is an example of a text ______
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A standard signal is one that has the approval of the users and/or a ______ agency
A standard signal is one that has the approval of the users and/or a ______ agency
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An analog signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e. ______
An analog signal is any continuous signal for which the time varying feature of the signal is a representation of some other time varying quantity, i.e. ______
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Analog signals represent quantities at any value between a specified set of upper and lower limits, and the 4–20 mA signal is one of the most commonly used industrial communications standards. It is used in the two-wire current loop that connects devices in an instrument circuit. The reader needs to become familiar with the terms: voltage, current, resistance, impedance, capacitive reactance, and ______.
Analog signals represent quantities at any value between a specified set of upper and lower limits, and the 4–20 mA signal is one of the most commonly used industrial communications standards. It is used in the two-wire current loop that connects devices in an instrument circuit. The reader needs to become familiar with the terms: voltage, current, resistance, impedance, capacitive reactance, and ______.
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The difference between uppercase and lowercase is ______.
The difference between uppercase and lowercase is ______.
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EBCDIC did not require a parity bit for error detection but instead used a different errordetection scheme—______.
EBCDIC did not require a parity bit for error detection but instead used a different errordetection scheme—______.
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Block Parity The vertical character format mentioned previously is based on the punched cards used in early data entry and programming. Because punched cards contained 80 columns and historically most data was on these cards, transmissions were in an 80-character '______'.
Block Parity The vertical character format mentioned previously is based on the punched cards used in early data entry and programming. Because punched cards contained 80 columns and historically most data was on these cards, transmissions were in an 80-character '______'.
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Parity means to count the number of 1s in a character. The agency determining the system’s operating specifications will have decided on which parity to use: “______” or “even.”
Parity means to count the number of 1s in a character. The agency determining the system’s operating specifications will have decided on which parity to use: “______” or “even.”
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The IBM 4 of 8 Code THE IBM 4 OF 8 CODE IS ILLUSTRATED IN TABLE 1 IN THIS CODE, THERE ARE FOUR 1S AND FOUR 0S —THAT IS 8 BITS, OR AN OCTET —FOR EACH CHARACTER. This arrangement was used to detect character errors, yet it carried a large overhead; that is, the ratio of bit patterns used for error detection to those for data transmission is high. International Telegraphic Alphabet #5 Also known as ______, the International Telegraphic Alphabet #5 does not make use of letter frequencies, as did the Morse code, the ITA2 Telegraph Code, and the IBM 4 of 8 Code.
The IBM 4 of 8 Code THE IBM 4 OF 8 CODE IS ILLUSTRATED IN TABLE 1 IN THIS CODE, THERE ARE FOUR 1S AND FOUR 0S —THAT IS 8 BITS, OR AN OCTET —FOR EACH CHARACTER. This arrangement was used to detect character errors, yet it carried a large overhead; that is, the ratio of bit patterns used for error detection to those for data transmission is high. International Telegraphic Alphabet #5 Also known as ______, the International Telegraphic Alphabet #5 does not make use of letter frequencies, as did the Morse code, the ITA2 Telegraph Code, and the IBM 4 of 8 Code.
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