CompTIA Net+ Module 3 Flashcards
1
Q
What is instantaneous data transmission ?
A
2
Q
What is serial data transmission ?
A
- Method of transmitting data one bit at a time over a communication channel.
- Types
- Synchronous = Data sent in continuous stream, synchronised by clock signal shared btw sender and receiver
- Asynchronous = Data sent one byte at a time, with start & stop bits added to indicate the beginning and end of each bytes.
3
Q
What is Synchronous and Asynchronous data transmission ?
A
4
Q
What is Parallel Data Transmission ?
A
- Method of transmitting multiple bits of data simultaneously across multiple channels.
- Higher speeds, short distance
- CPU and Memory (Internal Buses)
5
Q
What is Baseband Transmission ?
A
- Transmit signals over channel without modulating the signal into higher frequency.
- Occupies entire bandwidth
6
Q
What is Broadband Transmission ?
A
- refers to the high-speed transmission of data over a wide range of frequencies, enabling simultaneous data signals..
7
Q
What is a channel in communication systems ?
A
- Pathway for transmitting information.
- Physical Channel: eg twisted pair, coaxial cable, fiber optic).
- Logical Channel: A shared medium divided into multiple virtual channels (e.g., time-division multiplexing, frequency-division multiplexing).
8
Q
What is contention-based media access ?
A
9
Q
What is controlled media access ?
A
- refers to the process of regulating how multiple devices share a common communication medium to avoid collisions and ensure efficient data transmission
10
Q
What is multiplexing ? (controlled media access)
A
- Media access method that takes multiple signals and combines them over a shared medium.
- Time Division Multiplexing(TDM)
- Frequency Division Multiplexing (FDM)
- Code Division Multiplexing(CDM)
- Orthogonal Frequency Division Multiplexing(OFDM)
11
Q
What is Time Division Multiplexing ?
A
- Multiple signals share the same frequency band but are transmitted in diff time slots.
12
Q
What is Frequency Division Multiplexing ?
A
- in FDM, avail bandwidth divided into sep freq ranges (channels), each signal assigned to sep channel.
13
Q
What is Multiplexer (Mux) ?
A
- Is a device that combines multiple data signals from different sources and sends them over a single communication channel
14
Q
What is Polling ? (Controlled Media Access)
A
- A technique where a central device continuously checks other devices to see if they have data to send
- variation of polling is Demand Priority.
- Nodes signals state, data to transmit or not
15
Q
What is framing ?
A
- Framing is the process of dividing a stream of data into manageable, discrete units called frames.
- Key Functions:
Data Encapsulation: Wraps data in headers and trailers.
Error Detection/Correction: Adds checksums or CRCs.
Addressing: Includes source and destination addresses.
Flow Control: Regulates data transmission rate.
16
Q
In which order does the OSI model operate ?
A
- Sending Data = Descending order (Applications to Physical)
- Receiving Data = Ascending order (Physical to Applications)
17
Q
What is CSMA-CD ?
A
18
Q
What is CSMA-CA
A
- CSMA/CA stands for Carrier Sense Multiple Access with Collision Avoidance. It’s a network protocol used primarily in wireless networks to manage how data packets are transmitted over a shared communication medium, aiming to avoid collisions rather than detect them.
19
Q
What is Contention Domain ?
A
20
Q
What is Broadcast Domain ?
A
- Is a part of a network where any device can directly send broadcasts to all other devices within the same segment.
21
Q
Does Contention domain fall under Broadcast domain ?
A
22
Q
What is a clock cycle ?
A
- clock cycle = single electronic pulse of a CPU.
- CPU perform basic operation like writing data.
- Duration of a clock cycle = inverse of the clock frequency.
- In simpler terms, think of it as the heartbeat of the CPU, dictating how fast it can process instructions.
Modern CPUs can complete millions or even billions of clock cycles per second, which is why their speeds are often measured in megahertz (MHz) or gigahertz (GHz)3.
23
Q
How are frequency, bandwidth and digital signals related ?
A
- Bandwidth in digital communication is related to data rate (bps).
- Digital Signals transmitted using modulated carrier wave.
- High data rate req high bandwidth, more frequencies to represent rapidly changing 0’s and 1’s
24
Q
Why are higher frequencies used as carriers in modulation instead of lower frequencies.
A
- Efficient use of spectrum: more bandwidth at higher end of electromagnetic spectrum.
- Practical antenna size: Antenna size needs to be roughly the size of the wavelength of the signal.
- Lower freq travel further with less interference(less bandwidth and more noise) but higher frequency allows for more bandwidth and data capacity.
25
What is modulation ?
- Is a technique of superimposing a msg signal onto a carrier signal(Higher frequency) to transmit msg over longer distances.
26
List 3 types of modulation for analog signals.
- Frequency Modulation (FM): Changes the frequency of the carrier wave according to the msg signal
- Amplitude Modulation (AM): Changes the amplitude of the carrier wave according to the msg signal
- Phase Modulation (PM): Alters the phase of the carrier wave in relation to the msg signal
27
What bandwidth are assigned for fm radios in Australia and how do they work ?
- 200 kHz
- Eg, if FM station broadcast at centre frequency 100 MHz.
- Bandwidth = 200kHz (span from 99.9 MHz to 100.1 MHz)
28
What is stereo ?
- Stereo (stereophonic sound) is a method of sound reproduction that creates the illusion of multi-directional audio perspective by using two or more independent audio channels, typically played through two speakers (left and right).
29
What is a signal ?
- Data translated into electromagnetic information that can be transmitted and received by communiation devices.
30
What is analog signal ?
- A signal that carries data in a continuous waveform via either electromagnetic energy.
31
What is a codec ?
- A codec ("coder-decoder" or "compressor-decompressor") is a software algorithm that:
- Encodes (compresses) data into a compact format for storage or transmission.
- Decodes (decompresses) data back to its original form.
Types of Codecs:
- Audio Codecs: Compress audio files (e.g., MP3, AAC).
- Video Codecs: Compress video files (e.g., H.264, VP9).
- Image Codecs: Compress image files (e.g., JPEG, PNG).
- Text Codecs: Compress text data (e.g., ZIP, gzip).
32
List the modulation techniques for digital signals.
33
In what contexts are Kilobit (kb) and Kilobyte (KB) used?
