Data transmission Flashcards
(42 cards)
What is serial data transmission?
Serial data transmission sends data one bit at a time over a single wire or channel. It’s used for long-distance communication because it reduces interference and cost.
What is parallel data transmission?
Parallel data transmission sends multiple bits simultaneously using multiple wires. It is used for short distances, like inside a computer, because it is faster but more prone to interference.
What is simplex transmission?
Simplex transmission is one-way communication where data flows in only one direction (e.g., a keyboard sending data to a computer).
What is half-duplex transmission?
Half-duplex transmission allows data to be sent in both directions but not at the same time (e.g., walkie-talkies).
What is full-duplex transmission?
Full-duplex transmission allows data to be sent and received simultaneously in both directions (e.g., phone calls).
What is a data packet?
A data packet is a unit of data formatted for transmission over a network. It includes the header, payload, and trailer.
What is included in the header of a data packet?
The header contains control information such as source address, destination address, packet number, and protocol.
What is the payload in a data packet?
The payload is the actual data being transmitted (e.g., a part of an email or file).
What is the trailer in a data packet?
The trailer contains error-checking information like checksums or cyclic redundancy checks (CRC) to detect errors during transmission.
What is packet switching?
Packet switching splits data into packets that travel independently through the best available route on the network. It is efficient and robust but can cause delays or packet reordering.
What is circuit switching?
Circuit switching creates a dedicated communication path between two devices. It guarantees order and constant data rate but is less efficient for large networks.
What is error detection in data transmission?
Error detection involves methods like checksums, parity checks, and CRC to identify errors in transmitted data.
Why do errors occur in data transmission?
Due to interference like wire degradation, electromagnetic signals, bad weather, or physical barriers.
What are the three results of interference during transmission?
Data loss, data gain, and data change (flipped bits).
Why is error checking necessary?
Computers expect data in specific formats; errors can make data unreadable or misleading.
What is a parity check?
It determines if data has been corrupted by checking the number of 1s (odd/even parity).
What is the rule for even parity?
Total number of 1s in a byte (including parity bit) must be even.
What is a limitation of simple parity checks?
They can’t detect bit swaps that don’t change the number of 1s.
What is a parity byte?
A row of parity bits calculated vertically from each column in a block of data.
What is the purpose of a parity block?
It allows errors to be detected and pinpointed by checking both rows and columns.
What happens if an error is found using parity block?
It can be automatically fixed or a retransmission request is sent.
What is a checksum?
A value calculated from the data and sent with it to detect corruption.
How is a checksum used?
Receiver recalculates it and compares it to the original. A mismatch means an error occurred.
What is an echo check?
Receiver sends data back to the sender for comparison.
