Methods (1)
What is the difference between serial and parallel transmission?
Serial sends one bit at a time; parallel sends multiple bits at once.
What does USB stand for?
Universal Serial Bus
Why do we need error detection in data transmission?
To ensure data is received accurately without changes.
What is simplex transmission?
Data flows in one direction only.
What is skew in parallel transmission?
When bits arrive at slightly different times.
Which transmission type is faster over short distances — serial or parallel?
Parallel
Name one advantage of USB over older connectors.
Faster data transfer / automatic configuration / universal compatibility.
What is a parity bit?
An extra bit added to make the number of 1s either even or odd.
What is half-duplex transmission?
Data can flow both ways, but only one direction at a time.
Why is data broken into packets before being transmitted?
Easier to manage, route, and detect errors.
Why is serial transmission preferred for long distances?
It reduces interference and timing errors (skew).
What is one disadvantage of USB?
Limited cable length / some devices need special drivers.
Explain how a checksum works.
A calculated value is sent with data; the receiver recalculates and compares it.
What is full-duplex transmission?
Data flows in both directions simultaneously.
What is the role of a checksum in packet data?
Ensures packets haven’t been corrupted.
Why is serial transmission more reliable than parallel transmission for long-distance communication?
Because in parallel transmission, signal skew (where bits traveling on different wires arrive at slightly different times) causes timing errors over long distances.
Serial transmission sends bits one after another over a single channel, eliminating skew and maintaining higher reliability and data integrity, even at high speeds.
What type of data transmission does USB use?
Serial, full-duplex
List the error detection methods.
parity check
checksum
echo check
automatic repeat request (ARQ) - error control strategy
check digit
Give two real-life examples of full-duplex transmission.
Telephone call, Video conferencing, Live chat, Satellite communication systems, Headsets
Why is data accuracy critical in business or banking systems?
Because incorrect data can cause financial loss or security issues.
Explain how full-duplex serial transmission allows faster communication than half-duplex or simplex systems, and give one real-world example.
Full-duplex serial transmission allows data to be sent and received simultaneously using two separate channels, effectively doubling communication efficiency.
In contrast, half-duplex systems can only send or receive at one time, and simplex systems only send in one direction.
A USB connection or Wi-Fi communication is an example of full-duplex transmission.
What is one topic you remember from Chapter 1? (Free Pass)
Free Pass
Describe how Automatic Repeat Request (ARQ) works (Positive Acknowledgement Method).
Positive Acknowledgement Method:
Sending device transmits the first data packet
Receiving device receives it and checks for errors
Positive acknowledgment sent if data is error free
Receiving device sends the next data packet
If sending device does not receive a positive acknowledgement within a set timeframe, a timeout occurs until a positive acknowledgment is received
It will then stop resending the data
Which type of duplex is used in Wi-Fi communication?
Full-duplex
How is a check digit different from a checksum in error detection?
A check digit is a single digit added to the end of a numeric code (like a barcode or ISBN) and is calculated from the other digits. It helps detect simple input errors such as mistyped or transposed numbers.
A checksum is a larger value (often multiple bits or bytes) calculated from all the data being transmitted. It’s used to detect transmission or storage errors in blocks of data, not just single numbers.