Communication

• What is a symbol in communication systems?


  A symbol is a particular pattern of bits represented by a signal.
• What does Baud rate refer to in communication systems?


  Baud rate is the number of signal changes in the medium per second.
• How is 1 Baud defined?


  1 Baud is equal to 1 symbol change per second.
• What does bit rate refer to in communication mediums?


  Bit rate refers to the number of bits transmitted over the medium per second.
• How is a communication system's bit rate calculated?


  Bit rate is equal to Baud rate multiplied by the number of bits per signal.
• When will a communication medium's bit rate be higher than its Baud rate?


  The bit rate will be higher than the Baud rate if there is more than one bit per signal.
• What does bandwidth refer to in communication mediums?


  Bandwidth relates to the range of frequencies that a communication medium can transmit.
• What is the relationship between bandwidth and bit rate?


  Higher bandwidth results in a higher bit rate.
• How is latency measured in communication mediums?


  Latency is often measured in milliseconds.
• What does latency represent in a communication medium?


  Latency is the difference in time between an action being initiated and its effect being noticed.
• If you press a key and see the letter appear 26ms later, what does this indicate about latency?


  The latency in the link is 26ms.
• How does latency typically change with distance?


  Latency usually increases with distance.
• What is a protocol in communication systems?


  A protocol is a set of rules relating to communication between devices.
• Who decides upon and publishes communication protocols?


  International organizations decide upon and publish protocols.
• What is serial data transmission?


  In serial data transmission, data is sent one bit at a time over one communication line.
• When is serial data transmission frequently used?


  It is used for transmitting data over medium to long distances.
• What is parallel data transmission?


  Parallel data transmission uses numerous parallel communication lines to send multiple bits simultaneously.
• What happens to the time taken for bits to be transferred in parallel data transmission?


  The time taken for one bit to be transferred will differ slightly from line to line.
• What is skew in parallel data transmission?


  Skew refers to the issue where bits sent together may not be received together.
• When is skew worst in parallel data transmission?


  Skew is worst over long distances.
• What can extreme cases of skew lead to?


  Extreme cases of skew can lead to bits from different pulses overlapping, causing data corruption.
• Why are parallel communication mediums more expensive than serial ones?


  Parallel communication mediums use multiple lines, making them more expensive.
• When is parallel data transmission most often used?


  It is most often used over short distances, such as between parts of the processor and within RAM.
• What issue can occur with parallel data transmission due to tightly packed communication lines?


  Crosstalk can occur, where signals from one line leak into another.
• What are the advantages of serial data transmission over parallel data transmission?


  • Does not suffer from skew or crosstalk
  • More reliable over long distances
  • Cheaper to install than parallel mediums
• What is synchronous transmission?


  Synchronous transmission uses a clock signal shared with both the sender and receiver to time when signals are sent.
• Where is synchronous data transmission commonly used?


  Synchronous data transmission is used within buses of a computer’s processor in the fetch-execute cycle.
• What is the benefit of synchronous data transmission regarding signal order?


  Signals sent at regular intervals will be received in the same order they were sent.
• Why is synchronous data transmission suitable for real-time systems?


  Because it ensures that signals are received in the same order they were sent.
• What is asynchronous transmission?


  Asynchronous transmission uses start and stop bits to indicate the duration of a transmission without a shared clock.
• What are the start and stop bits in asynchronous transmission?


  The start bit can be a one or a zero, and the stop bit is always the opposite to the start bit.
• What must the sender do in asynchronous transmission regarding baud rate?


  The sender must use the same baud rate and synchronize their clocks for the duration of data transmission.