125 Questions
In data communications, how many modes of transmission are there?
Simplex, half-duplex, and duplex
What are the types of media used in data communications?
Electrical conductors, light pipes, and electromagnetic transmission
How are data communications topologies organized?
One-to-one, one-to-many, or many-to-many
What may members of a network have in terms of relationships?
No ranking or ranked
What is a digital signal defined as?
A signal with defined discrete states
Which coding system is an example of text coding?
ASCII
What did IBM design as one of the first digital communications codes?
IBM 4 of 8 Code
How many bits does ASCII use for its code?
7 bits
What was used for error detection in EBCDIC?
CRCC
What is the purpose of the 84th character, the block parity character, in the data block?
To add redundancy for error detection and correction
What is the main difference between a cyclic code and a checksum?
Cyclic codes have higher error-detection efficiency than checksums
In Binary Synchronous Communication protocol, what does control depend on?
Certain character combinations
What is the primary function of bit patterns in bit-oriented protocols?
To indicate the start and end of the information frame
What does the receiver protocol do upon detection of five consecutive 1s in a bit-oriented protocol?
Remove the 0 that follows
What was the primary focus of the first data transmission code mentioned in the text?
Error-detection scheme over data transmission efficiency
What is an example of a character-based protocol mentioned in the text?
IBM’s Synchronous Data Link Control (SDLC)
What is one distinguishing feature of Bi-Sync protocol?
It is one of the first proprietary protocols developed by IBM
What is a characteristic of bit-oriented protocols?
They use binary patterns for framing and synchronization
What distinguishes cyclic codes from linear codes?
Cyclic codes use polynomial arithmetic while linear codes do not
What was one reason cited in the text for duplex operation in Bi-Sync protocol?
Eliminating turnaround time
Data communications topologies are organized as ______, ______, or many-to-many
one-to-one
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” ______
circuit
In this mode, communication occurs only in one direction—never in the opposite direction; in figure 1-2 it is from Station A to ______
Station B
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 ______ 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
Parity
Many times the CRC-16 or CRC-CCITT is called a ______; however, they are actually cyclic codes, whereas a checksum was originally designed as a linear code
checksum
Some of these codes are cyclic, some are linear, some are quasi-cyclic, and some are ______
polynomial
One example of a character-based protocol is Binary Synchronous Communication. The IBM Bi-Sync protocol, one of the first and most widely used of the proprietary protocols, was developed to link the IBM 3270 line of terminals to IBM computers in a synchronous manner. The Bi-Sync protocol is character-based; control depends on certain character combinations, rather than on ______
bit patterns
Bit-oriented protocols use a concept called framing, where there are ______ before and after the information frame
bit patterns
The protocol only allows the frame to have this pattern at its start and ______
end
In framing, there is a binary pattern that is the start delimiter. There are also binary patterns that indicate the addressing and what type of frame it is, as well as some method of sequence numbering followed by the ______
user data
The receiver protocol, upon detection of five consecutive 1s, knows to remove the 0 that ______
follows
The first data transmission code devoted more overhead to the error-detection scheme than to the data ______
transmitted
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
The IBM Bi-Sync protocol, one of the first and most widely used of the proprietary protocols, was developed to link the IBM 3270 line of terminals to IBM computers in a synchronous manner. The Bi-Sync protocol is character-based; control depends on certain character combinations, rather than on ______
bit patterns
The Bi-Sync protocol is character-based; control depends on certain character combinations, rather than on ______
bit patterns
ASCII is a ______ code
7-bit
IBM 4 of 8 Code allowed error detection on a ______ basis
character-by-character
The International Telegraphic Alphabet #5 is also known as ______
ASCII
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. It does, however, use a numerically arranged code, in which the alphabet is in ascending order, which permits sorting operations and the like. ASCII is a ______ code.
7-bit
The parity bit was used for a number of years; however, the technological advantages to using an 8-bit data byte eliminated the need to use the B7 bit for parity. Today when parity is used, another bit is added to the 8 bits as the parity bit, making the signal 9 bits in ______.
length
Using 7 bits of an 8-bit structure, as ASCII does, will leave 1 bit extra and the parity bit is added to the 8-bit character, making it ______ bits.
9
The coding begins at U+0000 with standard ASCII characters, and then continues with Greek, Cyrillic, Hebrew, Arabic, Indic, and other ______.
scripts
Parity means to count the number of 1s in a ______.
character
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
Fixed-length character representations, of which ASCII and EBCDIC are examples, came about in the early 1960s and are still in wide use today. However ASCII was designed for English and, as communications are now global, there are many languages that require a larger number than 128 ______.
patterns
Because punched cards contained 80 columns and historically most data was on these cards, transmissions were in an 80-character ______.
block
Most computers using ASCII transmit 8 bits and use a ninth bit for parity, if ______ is used.
parity
Data communications topologies are organized as ______, ______, or many-to-many
one-to-one, one-to-many
Members of a network may have defined relationships: they may have no ranking or they may be ______
ranked
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” ______
circuit
ASCII is a 7-bit code. Its arrangement is well thought out; particularly in light of the technology available at the time it was designed. It was usually transmitted as an ______-bit signal with the “Most Significant Bit” reserved for parity—an error detection scheme
8
The difference between uppercase and lowercase is ______
bit
ASCII was designed for English and, as communications are now global, there are many languages that require a larger number than 128 ______
patterns
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 ______ 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
83rd
In framing, there is a binary pattern that is the start delimiter. There are also binary patterns that indicate the addressing and what type of frame it is, as well as some method of sequence numbering followed by the ______
information frame
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. It does, however, use a numerically arranged code, in which the alphabet is in ascending order, which permits sorting operations and the like. ASCII is a ______ code
7-bit
How are data communications topologies organized?
star, bus, or many-to-many
What is a characteristic of bit-oriented protocols?
framing with start and stop delimiters
In data communications, there are three modes of transmission: ______, half-duplex, and duplex
simplex
The coding begins at U+0000 with standard ASCII characters, and then continues with Greek, Cyrillic, Hebrew, Arabic, Indic, and other ______ scripts
languages
What is a digital signal defined as?
one with defined discrete states; no other state can exist
Parity means to count the number of 1s in a ______.
character
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 ______ 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
Parity
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
In framing, there is a binary pattern that is the start delimiter. There are also binary patterns that indicate the addressing and what type of frame it is, as well as some method of sequence numbering followed by the ______
user data
Bit-oriented protocols use a concept called framing, where there are ______ before and after the information frame
bit patterns
The protocol only allows the frame to have this pattern at its start and ______
end
The receiver protocol, upon detection of five consecutive 1s, knows to remove the 0 that ______
follows
The IBM Bi-Sync protocol, one of the first and most widely used of the proprietary protocols, was developed to link the IBM 3270 line of terminals to IBM computers in a synchronous manner. The Bi-Sync protocol is character-based; control depends on certain character combinations, rather than on ______
bit patterns
In data communications, there are three modes of transmission: ______, half-duplex, and duplex
simplex
The first data transmission code devoted more overhead to the error-detection scheme than to the data ______
transmitted
The Bi-Sync protocol is character-based; control depends on certain character combinations, rather than on ______
bit patterns
The protocol only allows the frame to have this pattern at its start and ______
end
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
What does the receiver protocol do upon detection of five consecutive 1s in a bit-oriented protocol?
remove the 0 that follows
In data communications, how many modes of transmission are there?
Three modes
What types of media are used in data communications?
Fiber optics, copper wires, and wireless transmission
What are the organized topologies in data communications?
Point-to-point, point-to-multipoint, and multipoint-to-multipoint
What does the Bi-Sync protocol control depend on?
Character combinations
What type of error-detection code may be called a checksum?
Any of the above
How is the efficiency of a checksum in detecting errors compared to a cyclic code?
Cyclic code is more efficient
What distinguishes CRC-16 or CRC-CCITT from a checksum?
They are linear codes
What is one distinguishing feature of Bi-Sync protocol?
It allows duplex transmission
What does the receiver protocol do upon detection of five consecutive 1s in a bit-oriented protocol?
It removes the 0 that follows
What is the purpose of the 84th character, the block parity character, in the data block?
It ensures even parity
What is the International Telegraphic Alphabet #5 also known as?
ITA2 Telegraph Code
How many bits does ASCII use for its code?
7
What is the purpose of the 84th character, the block parity character, in the data block?
Error detection
What distinguishes cyclic codes from linear codes?
Error-detection scheme
What is the primary function of bit patterns in bit-oriented protocols?
Error detection
What is a characteristic of bit-oriented protocols?
They use framing for data transmission
What does the receiver protocol do upon detection of five consecutive 1s in a bit-oriented protocol?
It removes a 0 that follows
What is a digital signal defined as?
A signal with discrete states
What was one reason cited in the text for duplex operation in Bi-Sync protocol?
Simultaneous bidirectional communication
The difference between uppercase and lowercase is ______.
Indicated by a specific bit pattern
Data communications topologies are organized as one-to-one, one-to-many, or many-to-many
True
The differences between a 'mode' and a 'circuit' are rather arbitrary
True
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
True
The purpose of communication is to transmit data from the source to the destination
True
ASCII was designed for English and is not suitable for global communications.
True
The International Telegraphic Alphabet #5 uses a numerically arranged code, allowing for sorting operations.
True
The IBM 4 of 8 Code and EBCDIC are both examples of text coding.
True
The parity bit in ASCII is used for error detection.
False
The 8-bit ASCII code is transmitted with an additional parity bit, making the signal 9 bits in length.
True
Unicode includes scripts such as Greek, Cyrillic, Hebrew, and Arabic.
True
The Bi-Sync protocol was developed for asynchronous communication.
False
The IBM 4 of 8 Code allowed error detection on a character-by-character basis.
True
EBCDIC requires a parity bit for error detection.
False
ASCII and EBCDIC are examples of fixed-length character representations.
True
The IBM Bi-Sync protocol was developed to link the IBM 3270 line of terminals to IBM computers in a synchronous manner.
True
The IBM 4 of 8 Code is an example of a digital communication code that used letter frequencies for efficiency.
False
Binary Synchronous Communication uses bit-oriented protocol
True
The Bi-Sync protocol is an example of a character-based protocol
True
The efficiency of a checksum in detecting errors is higher than with a cyclic code
False
The IBM Bi-Sync protocol was developed to link the IBM 3270 line of terminals to IBM computers in an asynchronous manner
False
The block parity character is used to determine if parity was met for all the characters in the block
True
The receiver protocol, upon detection of five consecutive 1s, knows to remove the 0 that follows
True
The first data transmission code devoted more overhead to the data transmitted than to the error-detection scheme
False
High Level Data Link Control is an example of a bit-oriented protocol
True
The International Telegraphic Alphabet #5 makes use of letter frequencies for error detection
False
ASCII uses 8 bits for its code
False
The Bi-Sync protocol uses duplex transmission
True
The receiver protocol, upon detection of five consecutive 1s, knows to remove the 1 that follows
False
Test your knowledge on communication concepts, elements, data transmission, and network topologies. Learn about the source, destination, data transmission media, and network member relationships.
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