Number Systems Quiz
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Questions and Answers

Data communications topologies are organized as ______

one-to-one (point-to-point), one-to-many (multi-drop), or many-to-many (networked)

The purpose of communication is to transmit ______ from the source to the destination(s)

data

In data communications, the media we use are: electrical conductors, light pipes, and electromagnetic transmission (usually referred to as ______)

wireless or radio

Point-to-point means just that, from one ______ to another, or directly from source to destination

<p>point to another</p> Signup and view all the answers

Binary (Base 2) is used in data transmission systems due to its simplicity as a ______ signal

<p>on-off</p> Signup and view all the answers

Analog signals, contrasting with binary digital signals, represent ______ quantities and are commonly used in industrial communications

<p>continuous</p> Signup and view all the answers

4–20 mA current loop signal is a widely used industrial communications standard for representing 0% to 100% of a ______

<p>range</p> Signup and view all the answers

Voltage is the difference in electrical potential, current performs the work, and resistance is the opposition a conductor offers to ______

<p>current</p> Signup and view all the answers

Impedance is the opposition a conductor offers to a changing current value, and is measured in ______

<p>Ohms</p> Signup and view all the answers

The ISA50 committee established the current loop as a standard due to its low impedance, greater noise immunity, and ability to power loop ______

<p>instruments</p> Signup and view all the answers

All number systems are digital, including octal (Base 8) and hexadecimal (Base 16), used for human readability in coding and data ______

<p>analysis</p> Signup and view all the answers

Bit patterns are organized into information through protocols or application programming ______

<p>interfaces</p> Signup and view all the answers

Text is organized into codings, such as American Standard Code for Information Interchange ______

<p>(ASCII)</p> Signup and view all the answers

Voltage is the difference in electrical ______, current performs the work, and resistance is the opposition a conductor offers to current

<p>potential</p> Signup and view all the answers

Impedance is the opposition a conductor offers to a changing current value, and is ______ in Ohms

<p>measured</p> Signup and view all the answers

The ISA50 committee established the current loop as a standard due to its low ______, greater noise immunity, and ability to power loop instruments

<p>impedance</p> Signup and view all the answers

ASCII uses ______ bits with an eighth bit reserved for parity

<p>7</p> Signup and view all the answers

EBCDIC uses ______ bits

<p>8</p> Signup and view all the answers

Unicode uses ______ bits

<p>16</p> Signup and view all the answers

EBCDIC uses ______ for special characters

<p>blank spaces</p> Signup and view all the answers

Unicode has more than ______ characters

<p>100,000</p> Signup and view all the answers

Morse code uses ______ for encoding

<p>symbols</p> Signup and view all the answers

Error correction in data transmission uses ______ for error detection

<p>CRC (Cyclic Redundancy Check)</p> Signup and view all the answers

ASCII has ______ characters, including uppercase and lowercase letters, digits, and some special characters

<p>128</p> Signup and view all the answers

EBCDIC does not require a parity bit but instead uses ______ for error detection

<p>CRC (Cyclic Redundancy Check)</p> Signup and view all the answers

Unicode is an industry standard for encoding that uses ______ bits

<p>16</p> Signup and view all the answers

ASCII uses ______ for representation of a character

<p>8 bits</p> Signup and view all the answers

EBCDIC is a proprietary system developed by ______

<p>IBM</p> Signup and view all the answers

Multi-drop systems consist of a master station and slave stations, also classified as a ______.

<p>network</p> Signup and view all the answers

In data communications, there are three modes of ______: simplex, half-duplex, and duplex.

<p>transmission</p> Signup and view all the answers

Simplex, or uni______al mode, allows communication in one ______.

<p>direction</p> Signup and view all the answers

Half-duplex mode allows communication in both directions but not at the same ______.

<p>time</p> Signup and view all the answers

Duplex mode allows communication in both directions ______.

<p>simultaneously</p> Signup and view all the answers

Serial transmission uses one ______ and sends bits one after the other.

<p>channel</p> Signup and view all the answers

Parallel transmission uses multiple ______ and sends multiple bits at once.

<p>channels</p> Signup and view all the answers

Parallel transmission has higher data ______ but faces challenges with logistics and simultaneous reception over distance.

<p>throughput</p> Signup and view all the answers

Cross-talk increases with signaling ______, making it increasingly difficult to obtain faster data ______s.

<p>rate</p> Signup and view all the answers

Most data ______ outside of computer cabinets are by serial transmission, while parallel transmission is used in computers.

<p>transmissions</p> Signup and view all the answers

Parallel transmission is being replaced by serial transmission ______ like USB.

<p>technologies</p> Signup and view all the answers

Digital signals have defined discrete ______, and binary digital signals have only two ______: a '1' or a '0'.

<p>states</p> Signup and view all the answers

Standard signals in measurement and control allow users to pick and choose among vendors with confidence, and enable manufacturers to build instruments for a larger user base

<p>standard</p> Signup and view all the answers

Digital Standard Signals include both open and proprietary standards in the telephone and ______ data communications area, but no open, all-______ standard has been established as an alternative to the analog 4–20 mA signal

<p>digital</p> Signup and view all the answers

______ is an international standard for industrial fieldbuses, which defines eight different fieldbuses, four of which are primarily used in process control (PROFIBUS PA and FOUNDATION Fieldbus)

<p>IEC 61158</p> Signup and view all the answers

______ is a physical and signal standard that continues to gain market share and acceptance in automation areas, and most fieldbuses and proprietary systems now provide networking services via ______

<p>Ethernet</p> Signup and view all the answers

Data Organization: Communications Codes are the components of data organization designed for interface with humans. IBM designed one of the first digital communications codes: the ______ in 1947

<p>IBM 4 of 8 Code</p> Signup and view all the answers

______, also known as International Telegraphic Alphabet (ITA) #5, is a 7-bit code that was designed in 1963 by the US government and gradually gained acceptance due to its numerically arranged code

<p>ASCII</p> Signup and view all the answers

IBM 4 of ______ Code is a proprietary code with ______ bits for each character, which was used to detect character errors but carried a large overhead

<p>8</p> Signup and view all the answers

______ does not make use of letter frequencies, but uses a numerically arranged code that permits sorting operations

<p>ITA #5 (ASCII)</p> Signup and view all the answers

ITA #5 (ASCII) is usually transmitted as an ______ signal with the Most Significant Bit reserved for parity, but today when parity is used, another bit is added as the parity bit, making the signal 9 bits in length

<p>8-bit</p> Signup and view all the answers

Data communications topologies are organized as one-to-one (point-to-point) or one-to-many (multi-drop) but not many-to-many (networked)

<p>False</p> Signup and view all the answers

Multi-drop topology more closely resembles a network than it does point-to-point topology

<p>True</p> Signup and view all the answers

In data communications, ASCII uses 7 bits for representation of a character

<p>True</p> Signup and view all the answers

EBCDIC uses a parity bit for error detection

<p>False</p> Signup and view all the answers

Multi-drop systems consist of a master station and slave stations, also classified as a network.

<p>True</p> Signup and view all the answers

Simplex, or unidirectional mode, allows communication in one direction.

<p>True</p> Signup and view all the answers

Parallel transmission uses multiple channels and sends multiple bits at once.

<p>True</p> Signup and view all the answers

Parallel transmission has higher data throughput but faces challenges with logistics and simultaneous reception over distance.

<p>True</p> Signup and view all the answers

Most data transmissions outside of computer cabinets are by serial transmission, while parallel transmission is used in computers.

<p>False</p> Signup and view all the answers

Parallel transmission is being replaced by serial transmission technologies like USB.

<p>True</p> Signup and view all the answers

Digital signals have defined discrete states, and binary digital signals have only two states: a '1' or a '0'.

<p>True</p> Signup and view all the answers

Half-duplex mode allows communication in both directions but not at the same time.

<p>True</p> Signup and view all the answers

Duplex mode allows communication in both directions simultaneously.

<p>True</p> Signup and view all the answers

Serial transmission uses one channel and sends bits one after the other.

<p>True</p> Signup and view all the answers

In data communications, there are three modes of transmission: simplex, half-duplex, and duplex.

<p>True</p> Signup and view all the answers

Cross-talk increases with signaling rate, making it increasingly difficult to obtain faster data rates.

<p>True</p> Signup and view all the answers

ASCII and EBCDIC are both based on fixed-length character representations and are still in use today

<p>True</p> Signup and view all the answers

Unicode uses 7 bits for character representation

<p>False</p> Signup and view all the answers

EBCDIC does not require a parity bit but instead uses CRC (Cyclic Redundancy Check) for error detection

<p>True</p> Signup and view all the answers

Unicode allows users to represent ASCII characters without issue

<p>True</p> Signup and view all the answers

ASCII, EBCDIC, and Unicode are all insufficient for representing multiple languages that require more than 128 patterns

<p>False</p> Signup and view all the answers

Morse code is discussed in the text as a historical context of code representations

<p>True</p> Signup and view all the answers

Error correction in data transmission uses CRC (Cyclic Redundancy Check) for error detection

<p>False</p> Signup and view all the answers

The focus of the text is on specific examples and applications of encoding systems

<p>False</p> Signup and view all the answers

EBCDIC uses 8 bits for character representation

<p>False</p> Signup and view all the answers

ASCII uses 7 bits for character representation with an eighth bit reserved for parity

<p>True</p> Signup and view all the answers

Unicode uses 16 bits for character representation

<p>True</p> Signup and view all the answers

EBCDIC is an industry standard for encoding, representing, and handling text

<p>False</p> Signup and view all the answers

Ethernet is a physical and signal standard that continues to lose market share and acceptance in automation areas

<p>False</p> Signup and view all the answers

IEC 61158 defines four different fieldbuses, all of which are primarily used in process control

<p>False</p> Signup and view all the answers

ASCII, also known as International Telegraphic Alphabet (ITA) #5, is an 8-bit code designed in 1963 by the US government

<p>False</p> Signup and view all the answers

IBM 4 of 8 Code is a proprietary code with 8 bits for each character and is used to detect character errors with low overhead

<p>False</p> Signup and view all the answers

ITA #5 (ASCII) is transmitted as a 9-bit signal with the Most Significant Bit reserved for parity

<p>True</p> Signup and view all the answers

Digital Standard Signals include both open and proprietary standards in the telephone and digital data communications area, and an open, all-digital standard has been established as an alternative to the analog 4–20 mA signal

<p>False</p> Signup and view all the answers

Standard signals in measurement and control do not allow users to pick and choose among vendors with confidence

<p>False</p> Signup and view all the answers

Data Organization: Communications Codes are not designed for interface with humans

<p>False</p> Signup and view all the answers

ASCII, also known as International Telegraphic Alphabet (ITA) #5, does not make use of letter frequencies, but uses a numerically arranged code that permits sorting operations

<p>True</p> Signup and view all the answers

EBCDIC is a proprietary code with 7 bits for each character, used to detect character errors with low overhead

<p>False</p> Signup and view all the answers

Ethernet is a physical and signal standard that continues to gain market share and acceptance in automation areas, and most fieldbuses and proprietary systems now provide networking services via Ethernet

<p>True</p> Signup and view all the answers

IEC 61158 is an international standard for industrial fieldbuses, which defines eight different fieldbuses, four of which are primarily used in process control (PROFIBUS PA and FOUNDATION Fieldbus)

<p>True</p> Signup and view all the answers

Binary (Base 2) is used in data transmission systems due to its complexity as a continuous signal

<p>False</p> Signup and view all the answers

4–20 mA current loop signal is a widely used industrial communications standard for representing 0% to 100% of a range

<p>True</p> Signup and view all the answers

Voltage is the difference in electrical potential, current performs the work, and resistance is the opposition a conductor offers to current

<p>True</p> Signup and view all the answers

Impedance is the opposition a conductor offers to a changing current value, and is measured in Volts

<p>False</p> Signup and view all the answers

The ISA50 committee established the current loop as a standard due to its high impedance, lower noise immunity, and inability to power loop instruments

<p>False</p> Signup and view all the answers

Analog signals, contrasting with binary digital signals, represent discrete quantities and are commonly used in industrial communications

<p>False</p> Signup and view all the answers

Bit patterns are organized into information through protocols or application programming interfaces

<p>True</p> Signup and view all the answers

Text is organized into codings, such as American Standard Code for Information Interchange (ASCII)

<p>True</p> Signup and view all the answers

All number systems are digital, including octal (Base 8) and hexadecimal (Base 16), used for human readability in coding and data analysis

<p>True</p> Signup and view all the answers

Digital signals have defined discrete levels, and binary digital signals have only two states: a '1' or a '0'

<p>True</p> Signup and view all the answers

Impedance is the opposition a conductor offers to a changing current value, and is measured in Ohms

<p>True</p> Signup and view all the answers

Voltage is the difference in electrical potential, current performs the work, and resistance is the opposition a conductor offers to current

<p>True</p> Signup and view all the answers

What are the three modes of transmission in data communications?

<p>Simplex, half-duplex, and duplex</p> Signup and view all the answers

What are the media types used in data communications?

<p>Electrical conductors, light pipes, and electromagnetic transmission</p> Signup and view all the answers

What are the two main topologies in data communications?

<p>One-to-one (point-to-point) and one-to-many (multi-drop)</p> Signup and view all the answers

What are the defined relationships among members of a network?

<p>Peers or ranked (master/slave)</p> Signup and view all the answers

What is the mode of transmission that allows communication in both directions but not at the same time?

<p>Half-duplex</p> Signup and view all the answers

Which mode of transmission allows communication in both directions simultaneously?

<p>Full-duplex</p> Signup and view all the answers

What type of transmission uses one channel and sends bits one after the other?

<p>Serial transmission</p> Signup and view all the answers

Which transmission method uses multiple channels and sends multiple bits at once?

<p>Parallel transmission</p> Signup and view all the answers

What is the primary challenge faced by parallel transmission over long distances?

<p>Logistical challenges</p> Signup and view all the answers

Which number system is used for human readability in coding and data analysis?

<p>Hexadecimal (Base 16)</p> Signup and view all the answers

What is the most widely used industrial communications standard for representing 0% to 100% of a range?

<p>4–20 mA current loop signal</p> Signup and view all the answers

What is the unit of measurement for impedance?

<p>Ohms</p> Signup and view all the answers

What did the ISA50 committee establish as a standard due to its low impedance, greater noise immunity, and ability to power loop instruments?

<p>Current loop</p> Signup and view all the answers

'Bit patterns are organized into information through protocols or application programming interfaces' - What is used to organize bit patterns into information?

<p>$j(x) = 4x + 9</p> Signup and view all the answers

What represents continuous quantities and is commonly used in industrial communications?

<p>Analog signals</p> Signup and view all the answers

What is used for data transmission systems due to its simplicity as an on-off signal?

<p>Binary (Base 2)</p> Signup and view all the answers

What is the purpose of communication?

<p>To transmit data from the source to the destination(s)</p> Signup and view all the answers

What does ASCII stand for?

<p>American Standard Code for Information Interchange</p> Signup and view all the answers

What does EBCDIC stand for?

<p>Extended Binary Coded Decimal Interchange Code</p> Signup and view all the answers

What does Unicode use for character representation?

<p>16 bits</p> Signup and view all the answers

'Digital signals have defined discrete states, and binary digital signals have only two states: a '1' or a '0'.' - What kind of signals have defined discrete states?

<p>Digital signals</p> Signup and view all the answers

Which of the following is a standard for industrial fieldbuses that defines eight different fieldbuses, four of which are primarily used in process control?

<p>PROFIBUS PA</p> Signup and view all the answers

What is the international standard for encoding, representing, and handling text that uses 8 bits for each character?

<p>EBCDIC</p> Signup and view all the answers

Which code was designed in 1963 by the US government and gradually gained acceptance due to its numerically arranged code?

<p>ASCII</p> Signup and view all the answers

Which signal standard has not been established as an alternative to the analog 4–20 mA signal?

<p>Ethernet</p> Signup and view all the answers

'ITA #5' is another name for which encoding system?

<p>ASCII</p> Signup and view all the answers

What is the opposition a conductor offers to a changing current value, measured in Volts?

<p>Impedance</p> Signup and view all the answers

What type of signals have defined discrete states, with binary digital signals having only two states: '1' or '0'?

<p>Digital signals</p> Signup and view all the answers

What type of transmission allows communication in both directions simultaneously?

<p>Duplex</p> Signup and view all the answers

Which of these is an example of a digital communications code designed for interface with humans?

<p>ASCII</p> Signup and view all the answers

What type of transmission allows communication in one direction only?

<p>Simplex</p> Signup and view all the answers

What is used to convert current to voltage and provide the measurement signal in a current loop?

<p>250-ohm resistor</p> Signup and view all the answers

How many characters does ASCII include?

<p>128 characters</p> Signup and view all the answers

How many bits does Unicode use for character representation?

<p>16 bits</p> Signup and view all the answers

What is the purpose of the eighth bit in ASCII?

<p>To provide parity</p> Signup and view all the answers

What is the main limitation of ASCII and EBCDIC in representing multiple languages?

<p>Limited to 256 patterns</p> Signup and view all the answers

Which encoding system does not require a parity bit but uses CRC for error detection?

<p>EBCDIC</p> Signup and view all the answers

What is the total number of characters covered by Unicode?

<p>&gt;100,000 characters</p> Signup and view all the answers

How many bits are used by EBCDIC for character representation?

<p>8 bits</p> Signup and view all the answers

What is the number of bits used by ASCII for character representation?

<p>7 bits</p> Signup and view all the answers

What type of error detection is used by EBCDIC?

<p>Cyclic Redundancy Check (CRC)</p> Signup and view all the answers

What is the main limitation of ASCII in representing multiple languages?

<p>Limited to 128 patterns</p> Signup and view all the answers

Explain the concept of parity and its role in error detection in data communication systems.

<p>Parity is a means of error detection in data communication systems. It involves adding an extra bit (parity bit) to the data structure to ensure a specific number of 1s in the character. The system can use 'odd' or 'even' parity, and the parity bit is chosen to make the total number of 1s in the character (including the parity bit) either odd or even. If the received data does not have the correct parity, an error is detected.</p> Signup and view all the answers

Describe the IBM 4 of 8 Code and its significance in error detection.

<p>The IBM 4 of 8 Code is an early form of error detection used to detect errors in transmitted data. It checks if any character has more or less than four 1s in 8 bits. If an error is detected, the entire block of data (84 characters) is retransmitted. This code was significant in early data communication systems for ensuring more reliable data transmission.</p> Signup and view all the answers

What is block parity in the context of data communication, and how is it related to the format of transmitted data?

<p>Block parity refers to the use of a vertical character format in data transmission systems, often based on the 80-column structure of punched cards. Due to historical data storage on punched cards, transmissions were organized in 80-character 'blocks.' If an error was detected in any character within the block, the entire block (84 characters) would be retransmitted, emphasizing the significance of error detection and retransmission in early data communication.</p> Signup and view all the answers

Discuss the relationship between the properties of the transmission medium, error probability, and the need for error detection in data communication systems.

<p>The probability of error in data transmission depends on the properties of the transmission medium and the signal. Different media and signal properties can result in varying error probabilities. As a result, error detection mechanisms, such as parity and block parity, are crucial in identifying and correcting errors that occur during data transmission.</p> Signup and view all the answers

What is the main means of synchronizing the start-stop bits within each character in the old 'start-stop' teletypewriter signal?

<p>motor speed</p> Signup and view all the answers

What is the baud rate?

<p>the line modulation rate; that is, the number of signal changes per second that are placed on the communication medium in a given time</p> Signup and view all the answers

What is the difference between baud rate and bits per second?

<p>Baud rate is the line modulation rate, while bits per second is the data transmission rate of the device that is transmitting or that a device is capable of receiving</p> Signup and view all the answers

What type of transmission uses bit timing and accounts for each bit of data?

<p>synchronous transmission</p> Signup and view all the answers

What technique is used by modems running at 33.6 Kbps to achieve their higher data rate?

<p>trellis encoding</p> Signup and view all the answers

What is the primary benefit of duplex operation in the Bi-Sync protocol?

<p>eliminating the turnaround time, because the transmitter could do nothing else until it received a response to its transmitted block</p> Signup and view all the answers

What is the cost of data storage approximately in 1980 dollars when Bi-Sync was developed?

<p>one US dollar per bit</p> Signup and view all the answers

What is the primary means of synchronizing the start-stop bits within each character in the old 'start-stop' teletypewriter signal?

<p>motor speed</p> Signup and view all the answers

What is the clock signal typically transmitted along with in synchronous transmission?

<p>the data, usually in the transition of data from one state to another</p> Signup and view all the answers

What is the data transmission rate of a device that is transmitting or that a device is capable of receiving?

<p>bits per second</p> Signup and view all the answers

What is the term used to describe a change in a transmission medium signaling state?

<p>baud per second</p> Signup and view all the answers

What technique is used to ensure data state transitions in most modern hardware?

<p>scrambler</p> Signup and view all the answers

What is the purpose of Bi-Sync's transparent mode?

<p>To allow control characters to be ignored until the receiver detects several data link escape characters.</p> Signup and view all the answers

What is the distinguishing feature of bit-oriented protocols in modern communications?

<p>They make the protocol independent of the transmitted message type.</p> Signup and view all the answers

What is the purpose of the start delimiter in framing for bit-oriented protocols?

<p>To indicate the beginning of the information frame.</p> Signup and view all the answers

What is the significance of the frame check sequence (FCS) in bit-oriented protocols?

<p>It is used for error checking the user data.</p> Signup and view all the answers

What is the purpose of the flag characters in LAP-B protocol?

<p>To 'frame' the data by indicating the beginning and end of each transmitted frame.</p> Signup and view all the answers

How does the LAP-B protocol ensure the use of the start and end pattern in frames?

<p>By using a technique called zero insertion or bit stuffing.</p> Signup and view all the answers

What functionality does the LAP-B protocol provide for medium-induced errors?

<p>Detection through the frame check sequence and identification by frame number.</p> Signup and view all the answers

What is the primary similarity between LAP-B, ADCCP, and HDLC protocols?

<p>They are quite similar in structure and format.</p> Signup and view all the answers

What is the purpose of a stop delimiter in framing for bit-oriented protocols?

<p>To indicate the end of the information frame.</p> Signup and view all the answers

In the context of bit-oriented protocols, what does it mean for user data to be encapsulated?

<p>It means the user data is surrounded by the protocol, framing the data.</p> Signup and view all the answers

What is the significance of zero insertion in bit-oriented protocols?

<p>It is used to ensure that five consecutive 1 bits in the data stream are followed by a 0.</p> Signup and view all the answers

What is the impact of medium-induced errors on the receiver in LAP-B protocol?

<p>The receiver ignores an errored frame and notifies the transmitter upon receiving the next good frame that it is not the one it anticipated.</p> Signup and view all the answers

What is the purpose of a checksum in data communications?

<p>A checksum is used for error detection in data communications.</p> Signup and view all the answers

What are the different error detecting codes mentioned in the text?

<p>The text mentions checksum, CRCC, and various other cyclic, linear, quasi-cyclic, and polynomial codes for error detection.</p> Signup and view all the answers

Explain the Automatic Repeat Query (ARQ) method for error correction mentioned in the text.

<p>The ARQ method involves the transmitter sending a frame, the receiver sending an ACK or NAK, and the transmitter retransmitting if an error is detected or if there is no response from the receiver.</p> Signup and view all the answers

What is the purpose of Forward Error Correction (FEC) in data communications?

<p>FEC is used for simplex or noisy transmissions and requires analyzing and designing error-correcting algorithms, but it can have high error-detection and location overhead.</p> Signup and view all the answers

Define protocols in the context of data communications.

<p>Protocols are accepted procedures used in personal interactions and data communications.</p> Signup and view all the answers

What is the significance of half-duplex mode in human communication?

<p>Humans are effectively half-duplex and typically cannot multitask listening and speaking effectively.</p> Signup and view all the answers

What can result from frame corruption in data communications?

<p>Frame corruption can result in the receiver not recognizing the frame, leading to no response.</p> Signup and view all the answers

How does a receiver detect duplicate frames in data communications?

<p>The receiver can detect duplicate frames with the same frame number and drop one, sending another ACK.</p> Signup and view all the answers

Why is the efficiency of checksum lower compared to cyclic codes?

<p>Checksum is less complex than cyclic codes, but its efficiency is not as high.</p> Signup and view all the answers

What happens when a timeout occurs in data communications?

<p>When no response is received, the transmitter assumes an error and resends the frame.</p> Signup and view all the answers

What is the purpose of Modulo abbreviation in different programming languages?

<p>The Modulo abbreviation varies by programming language, such as MOD in COBOL and % in C-style languages.</p> Signup and view all the answers

Why is Forward Error Correction (FEC) used for simplex or noisy transmissions?

<p>FEC is used for simplex or noisy transmissions due to its high error-detection and location overhead.</p> Signup and view all the answers

What are the two types of parity used in parity checking for error detection in data communication?

<p>Vertical and horizontal parity</p> Signup and view all the answers

What type of errors can parity checking detect?

<p>Single-bit errors</p> Signup and view all the answers

What is the primary drawback of parity checking?

<p>It is less effective for multiple-errored bits and adds significant overhead to data transmission</p> Signup and view all the answers

What is the purpose of Automatic Retransmission Queries (ARQ) in error correction?

<p>To correct errors once they are detected by requiring the transmission device to store the last transmitted block and respond to the receiver's request to retransmit the block</p> Signup and view all the answers

How does Cyclic Redundancy Check (CRC) differ from parity checking in terms of efficiency?

<p>CRC is a more efficient error detection scheme than parity checking</p> Signup and view all the answers

What does the pick-off point in CRC depend on?

<p>The application and the error behavior of the communications channel</p> Signup and view all the answers

How does the overhead of CRC compare to parity checking?

<p>CRC adds less overhead than parity checking, using only a few bits per character</p> Signup and view all the answers

What type of error does CRC excel at detecting compared to parity checking?

<p>CRC is more effective than parity checking for detecting multiple-errored bits</p> Signup and view all the answers

What is the primary difference between Checksum and CRC?

<p>Checksum is a linear code, while CRC is a cyclic code</p> Signup and view all the answers

What is the calculation process for generating a checksum?

<p>Converting all bits in a block to their corresponding binary numbers and summing them using modulo addition</p> Signup and view all the answers

Why is CRC more widely used in modern data communications than checksum?

<p>Due to its superior error detection capabilities</p> Signup and view all the answers

In what type of communication is CRC particularly used?

<p>Industrial settings</p> Signup and view all the answers

What is the purpose of parity in error detection in data communication systems?

<p>To ensure an even number of 1s in a character</p> Signup and view all the answers

What is the IBM 4 of 8 Code used for?

<p>Detecting errors by checking for more or less than four 1s in 8 bits</p> Signup and view all the answers

What is the significance of the vertical character format based on punched cards?

<p>It was based on the 80-column format of punched cards and was used for error detection and retransmission</p> Signup and view all the answers

What does the addition of a parity bit do to an 8-bit character?

<p>Adds an extra bit to make it a 9-bit structure</p> Signup and view all the answers

What is the primary difference between Bi-Sync and LAP-B protocols?

<p>Bi-Sync is character-oriented, while LAP-B is bit-oriented</p> Signup and view all the answers

What technique does LAP-B use to ensure that the frame starts and ends with the flag?

<p>Bit stuffing</p> Signup and view all the answers

How are medium-induced errors detected and identified in bit-oriented protocols like LAP-B?

<p>Through frame check sequence and frame number</p> Signup and view all the answers

What does it mean for user data to be encapsulated in framing for bit-oriented protocols?

<p>User data is included within the framing structure</p> Signup and view all the answers

What is the primary reason for bit-oriented protocols being more commonly used than character-based protocols?

<p>Independence from the data stream contents</p> Signup and view all the answers

What is the purpose of the eighth bit in ASCII?

<p>Parity checking</p> Signup and view all the answers

What type of errors can be detected through parity checking?

<p>Single-bit errors only</p> Signup and view all the answers

What does Bi-Sync protocol depend on?

<p>Character-oriented codes</p> Signup and view all the answers

What does LAP-B use for framing?

<p>Start and stop delimiters</p> Signup and view all the answers

What are bit-oriented protocols primarily used in?

<p>Point-to-point and multi-drop systems</p> Signup and view all the answers

How many frames does LAP-B allow to be transmitted before the first frame must be acknowledged?

<p>128</p> Signup and view all the answers

What is the primary difference between cyclic redundancy checks (CRC) and parity checking?

<p>CRC uses a binary polynomial to generate a check character, while parity checking involves adding framing characters and a block parity character to each data block.</p> Signup and view all the answers

What is the main disadvantage of using parity checking for error detection in data communication?

<p>Parity checking adds significant overhead to the data transmission, requiring an additional parity bit for each character.</p> Signup and view all the answers

What distinguishes checksum from cyclic redundancy checks (CRC) as an error-detection code?

<p>Checksum is a linear code calculated by summing all bits in a block using modulo addition, while CRC uses vertical and horizontal parity bits for error detection.</p> Signup and view all the answers

What makes automatic retransmission queries (ARQ) an important method for error correction in data communication?

<p>ARQ requires the transmission device to store the last transmitted block and respond to the receiver's request to retransmit the block.</p> Signup and view all the answers

Why is cyclic redundancy check (CRC) considered a more efficient error detection scheme than parity checking?

<p>CRC adds less overhead than parity checking, using only a few bits per character.</p> Signup and view all the answers

What is the primary difference between asynchronous and synchronous transmission?

<p>Asynchronous transmission uses start and stop bits per character, while synchronous transmission uses bit timing.</p> Signup and view all the answers

What is the difference between baud rate and bits per second?

<p>Baud rate is the line modulation rate, while bits per second is the number of signal changes per second.</p> Signup and view all the answers

What is the purpose of trellis encoding in synchronous modems?

<p>To achieve higher data rates by sending a signal state for each 56-bit combination.</p> Signup and view all the answers

What characterizes Binary Synchronous Communication (Bi-Sync) protocol?

<p>It is a synchronous, character-based protocol developed for IBM systems and requires duplex transmission.</p> Signup and view all the answers

Why did efficient data transmission become crucial when Bi-Sync was developed?

<p>As a result of the significant expense of data storage at that time.</p> Signup and view all the answers

What are communication protocols primarily used for?

<p>Controlling electronic message handling and ensuring efficient data storage</p> Signup and view all the answers

Which statement accurately describes character-based protocols like Binary Synchronous Communication (Bi-Sync)?

<p>They use control based on certain character combinations and require the transmitting terminal to store multiple blocks of data.</p> Signup and view all the answers

What distinguishes Bi-Sync as a synchronous, character-based protocol developed for IBM systems?

<p>It requires duplex transmission for effective communication.</p> Signup and view all the answers

What coding technique does Trellis encoding employ in synchronous modems?

<p>It achieves higher data rates by sending a signal state for each 56-bit combination.</p> Signup and view all the answers

Which statement accurately describes baud rate and bits per second?

<p>Baud rate is the line modulation rate, while bits per second is the number of signal changes per second.</p> Signup and view all the answers

What is the purpose of Forward Error Correction (FEC) in data communications?

<p>To correct errors in the received data without the need for retransmission</p> Signup and view all the answers

Which method is used for error correction in Automatic Repeat Query (ARQ) in data communications?

<p>Transmitter retransmits if error detected or no response</p> Signup and view all the answers

What type of error detection code is checksum?

<p>Block character used for error detection</p> Signup and view all the answers

What distinguishes Forward Error Correction (FEC) from Automatic Repeat Query (ARQ) in data communications?

<p>FEC corrects errors without retransmission, while ARQ requests retransmission</p> Signup and view all the answers

What is the primary difference between checksum and Cyclic Redundancy Check (CRC) in terms of their error-detection capabilities?

<p>CRC can detect a wider range of errors compared to checksum</p> Signup and view all the answers

What happens when a frame corruption occurs in data communications?

<p>Receiver may not recognize the frame, leading to no response</p> Signup and view all the answers

What type of transmissions are suitable for Forward Error Correction (FEC)?

<p>For simplex or noisy transmissions</p> Signup and view all the answers

What does Automatic Repeat Query (ARQ) rely on to determine whether a frame needs to be retransmitted?

<p>Acknowledgment (ACK) or Negative Acknowledgment (NAK) from the receiver</p> Signup and view all the answers

Study Notes

  • The 250-ohm resistor in a current loop is used for converting current to voltage, which powers the loop instrument and provides the measurement signal.

  • Standard signals in measurement and control allow users to pick and choose among vendors with confidence, and enable manufacturers to build instruments for a larger user base.

  • Digital Standard Signals include both open and proprietary standards in the telephone and digital data communications area, but no open, all-digital standard has been established as an alternative to the analog 4–20 mA signal.

  • IEC 61158 is an international standard for industrial fieldbuses, which defines eight different fieldbuses, four of which are primarily used in process control (PROFIBUS PA and FOUNDATION Fieldbus).

  • Ethernet is a physical and signal standard that continues to gain market share and acceptance in automation areas, and most fieldbuses and proprietary systems now provide networking services via Ethernet.

  • Data Organization: Communications Codes are the components of data organization designed for interface with humans. IBM designed one of the first digital communications codes: the IBM 4 of 8 Code in 1947.

  • ASCII, also known as International Telegraphic Alphabet (ITA) #5, is a 7-bit code that was designed in 1963 by the US government and gradually gained acceptance due to its numerically arranged code.

  • IBM 4 of 8 Code is a proprietary code with 8 bits for each character, which was used to detect character errors but carried a large overhead.

  • ITA #5 (ASCII) does not make use of letter frequencies, but uses a numerically arranged code that permits sorting operations.

  • ITA #5 (ASCII) is usually transmitted as an 8-bit signal with the Most Significant Bit reserved for parity, but today when parity is used, another bit is added as the parity bit, making the signal 9 bits in length.

  • All number systems are digital, including octal (Base 8) and hexadecimal (Base 16), used for human readability in coding and data analysis

  • Binary (Base 2) is used in data transmission systems due to its simplicity as a on-off signal

  • Bit patterns are organized into information through protocols or application programming interfaces

  • Text is organized into codings, such as American Standard Code for Information Interchange (ASCII)

  • Analog signals, contrasting with binary digital signals, represent continuous quantities and are commonly used in industrial communications

  • 4–20 mA current loop signal is a widely used industrial communications standard for representing 0% to 100% of a range

  • Voltage is the difference in electrical potential, current performs the work, and resistance is the opposition a conductor offers to current

  • Impedance is the opposition a conductor offers to a changing current value, and is measured in Ohms

  • The ISA50 committee established the current loop as a standard due to its low impedance, greater noise immunity, and ability to power loop instruments.

  • All number systems are digital, including octal (Base 8) and hexadecimal (Base 16), used for human readability in coding and data analysis

  • Binary (Base 2) is used in data transmission systems due to its simplicity as a on-off signal

  • Bit patterns are organized into information through protocols or application programming interfaces

  • Text is organized into codings, such as American Standard Code for Information Interchange (ASCII)

  • Analog signals, contrasting with binary digital signals, represent continuous quantities and are commonly used in industrial communications

  • 4–20 mA current loop signal is a widely used industrial communications standard for representing 0% to 100% of a range

  • Voltage is the difference in electrical potential, current performs the work, and resistance is the opposition a conductor offers to current

  • Impedance is the opposition a conductor offers to a changing current value, and is measured in Ohms

  • The ISA50 committee established the current loop as a standard due to its low impedance, greater noise immunity, and ability to power loop instruments.

  • The text discusses various encoding systems for text representation, specifically ASCII, EBCDIC, and Unicode.

  • ASCII (American Standard Code for Information Interchange) uses 7 bits with an eighth bit reserved for parity; it has 128 characters, including uppercase and lowercase letters, digits, and some special characters.

  • To determine the binary representation of a character, trace its position vertically and obtain the first three bits, then travel horizontally to obtain the remaining bits.

  • EBCDIC (Extended Binary Coded Decimal Interchange Code) is a proprietary system developed by IBM and uses the blank spaces for special characters. It does not require a parity bit but instead uses CRC (Cyclic Redundancy Check) for error detection.

  • ASCII and EBCDIC are based on fixed-length character representations and are still in use today. However, they are insufficient for representing multiple languages that require more than 128 patterns.

  • Unicode is an industry standard for encoding, representing, and handling text, with more than 100,000 characters covering multiple symbol sets. It uses 16 bits and allows users to represent ASCII characters without issue.

  • The text discusses the historical context of code representations, from Morse code to fixed-length character representations. It also touches upon the issue of communication between systems using different encoding systems and the need for software or hardware translators.

  • The text briefly discusses the importance of error correction in data transmission, using the example of a scratch on a DVD causing alterations to the music.

  • Throughout the text, the focus is on the encoding systems themselves and their key features, rather than specific examples or applications.

  • The text discusses error detection and correction in data communication using vertical and horizontal parity checking and cyclic redundancy checks (CRC).

  • Parity checking involves adding framing characters and a block parity character to each data block for error detection. Vertical parity is determined for each character in the block, and horizontal parity is determined for each bit. The vertical and horizontal parity bits are used to check for parity errors in the block.

  • Parity checking can detect single-bit errors but is less effective for multiple-errored bits. It adds significant overhead to the data transmission, requiring an additional parity bit for each character.

  • Automatic retransmission queries (ARQ) are used to correct errors once they are detected. ARQ requires the transmission device to store the last transmitted block and respond to the receiver's request to retransmit the block.

  • Cyclic redundancy checks (CRC) are a more efficient error detection scheme than parity checking. CRC involves generating a check character from a data block using a binary polynomial. The receiver computes its own CRC and compares it to the transmitted CRC to detect errors.

  • The primary difference between various CRCs is the "pick-off point," which depends on the application and the error behavior of the communications channel.

  • CRC adds less overhead than parity checking, using only a few bits per character.

  • CRC is used in modern data communications, particularly in industrial settings, and is more effective than parity checking for detecting multiple-errored bits.

  • Checksum is an error-detection code that can be considered a type of CRC, but it is a linear code rather than a cyclic code. Checksum is calculated by converting all bits in a block to their corresponding binary numbers and summing them using modulo addition. The result is the checksum, which is added to the data block for error detection.

  • CRC is more widely used in modern data communications than checksum due to its superior error detection capabilities.

  • The text discusses error detection and correction in data communication using vertical and horizontal parity checking and cyclic redundancy checks (CRC).

  • Parity checking involves adding framing characters and a block parity character to each data block for error detection. Vertical parity is determined for each character in the block, and horizontal parity is determined for each bit. The vertical and horizontal parity bits are used to check for parity errors in the block.

  • Parity checking can detect single-bit errors but is less effective for multiple-errored bits. It adds significant overhead to the data transmission, requiring an additional parity bit for each character.

  • Automatic retransmission queries (ARQ) are used to correct errors once they are detected. ARQ requires the transmission device to store the last transmitted block and respond to the receiver's request to retransmit the block.

  • Cyclic redundancy checks (CRC) are a more efficient error detection scheme than parity checking. CRC involves generating a check character from a data block using a binary polynomial. The receiver computes its own CRC and compares it to the transmitted CRC to detect errors.

  • The primary difference between various CRCs is the "pick-off point," which depends on the application and the error behavior of the communications channel.

  • CRC adds less overhead than parity checking, using only a few bits per character.

  • CRC is used in modern data communications, particularly in industrial settings, and is more effective than parity checking for detecting multiple-errored bits.

  • Checksum is an error-detection code that can be considered a type of CRC, but it is a linear code rather than a cyclic code. Checksum is calculated by converting all bits in a block to their corresponding binary numbers and summing them using modulo addition. The result is the checksum, which is added to the data block for error detection.

  • CRC is more widely used in modern data communications than checksum due to its superior error detection capabilities.

  • Checksum: a block character used for error detection, less complex than cyclic codes, efficiency is not as high

  • Modulo abbreviation varies by programming language: MOD in COBOL, % in C-style languages

  • Error detecting codes include checksum, CRCC, and various other cyclic, linear, quasi-cyclic, and polynomial codes

  • Automatic Repeat Query (ARQ) method for error correction: transmitter sends frame, receiver sends ACK or NAK, transmitter retransmits if error detected or no response

  • Frame corruption can result in receiver not recognizing frame, leading to no response

  • Timeout occurs when no response is received, transmitter assumes error and resends frame

  • Receiver can detect duplicate frames with same frame number and drop one, sending another ACK

  • Forward error correction (FEC) used for simplex or noisy transmissions, requires analyzing and designing error-correcting algorithms, can have high error-detection and location overhead

  • Protocols are accepted procedures, used in personal interactions and data communications, humans are effectively half-duplex and typically cannot multitask listening and speaking effectively.

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Description

Test your knowledge of binary, decimal, octal, and hexadecimal number systems. Explore the significance of each system in coding, data analysis, and data transmission.

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