Unit 2- Connectivity Flashcards
What is satellite communication?
- Satellite communication uses radio waves for wireless communication
- Signals are sent between satellites and ground stations on earth
- Ground stations transmit the radio wave to antenna within or connected to a digital devices
What are the advantages of satellite communication?
The advantage of satellite communication is that the service is always available
What are the disadvantages if satellite communication?
The disadvantages of satellite communication is that the service can be interrupted by weather conditions and signals do not pass through solid objects
What is satellite television?
Digital Video Broadcasting (DVB) is the international standard for broadcasting digital television
Digital Video Broadcasting-Satellite (DVB-S) is an example of DVB
A video signal is sent from a broadcaster to a satellite, and sent back to earth to an antenna connected to a set-top box or directly to a television
The set-top box or television decodes the signal to make it watchable
What is a digital television and radio?
Digital Video Broadcasting Terrestrial (DVB-T) and Digital Audio Broadcasting (DAB) are methods of transmitting video and audio signals from transmitters to an antenna
Transmitters are based on earth
Once received by the antenna, signals travel through wires to a television or radio receiver which decodes the signal and converts it into video and/or audio
What is the advantage of digital television and radio?
- Improved video/audio quality
- Access to more channels/stations
What are some examples of wired methods of communication?
- high definition multi media interface
- mini-jack
- ethernet
- universal serial bus
What is the use of High Definition Multimedia Interface (HDMI)?
High definition video and audio signals
What is the use of Sony/Phillips Digital Interface Format (S/PDIF)?
Transmit digital audio streams between devices
What is the use of Mini-jack?
3.5mm jack commonly used to connect headphones, speakers and microphones to devices
What is the use of Ethernet?
Networking standard for connecting devices to a local area network (LAN)
What is the use of Universal Serial Bus (USB)?
Connecting and powering various devices such as printers, flash drives, keyboards, mice etc.
What are some examples of wireless methods of communication?
Wireless fidelity (WIFI), Bluetooth, Infra-red (IR)
What is the use of Wireless Fidelity (Wi-Fi)?
A wireless method of connecting devices to a local area network (LAN)
What is the use of Infra-red (IR)?
Transmits tiny amounts of data over very short distances
What is the use of Bluetooth?
Allows two devices to connect to each other over very short distances
What is the use of Near Field Communication (NFC)?
Use close proximity RFID (radio frequency identification)
What is the use of 4G and 5G?
Provides internet access to mobile devices
What is a local area network (LAN)?
A local area network (LAN) is a network which has a small geographical area (under 1 mile)
All of the hardware is owned by the company/organisation/household using it
LANs will use unshielded twisted pair (UTP) cable, fibre optic cable or wireless connections (Wi-Fi)
What are the advantages of LANs?
- Allows centralised management of updates, backups and software installations
- Can secure its devices with the use of firewalls, antivirus software and other security features to prevent unauthorised access
- Allows users on the network to share resources such as printers and other peripherals
- Allows the users of the network to collaborate and share files and folders
What are the disadvantages of LANs?
- If hardware fails, the network may not function properly or even at all
- Networks are more prone to attacks than standalone computers
- Access to data and peripherals can be slow depending on network traffic
- Require maintenance to ensure that software is up to date, upgrades and backups which can be costly
What is wide area network?
A wide area network (LAN) is a network which has a large geographical area (over 1 mile)
They are a collection of LANs joined together
The computers on a WAN are connected via routers
The hardware used to connect the networks together is not all owned by the company/organisation/household using it.
For example, telephone lines owned by telecommunication companies
WANs will use fibre optic cable, telephone lines and satellite to connect the LANs together
What is a PAN?
A personal area network (PAN) is a network that is used for transmission of data between devices in close proximity
A PAN has a very short range (10 metres)
Bluetooth is the most widely used PAN
What are some typical examples of devices which make use of a PAN are
Wireless headphones
Mobile phones
Tablet
Laptop etc.
What is tethering?
Tethering is when a host device shares its internet connection with other connected devices
Commonly used by mobile devices to share its mobile data connection to devices such as laptops and tablets
Tethering can be enabled or disabled as part of the mobile contract
Some network providers charge extra to use this feature
What is WIFI?
Wireless fidelity (Wi-Fi) is a common standard for wireless networks
Wi-Fi is common in most homes and offices to connect devices such as laptops, tablets & smart phones
Using Wi-Fi, devices communicate with a hotspot or a wireless access point (WAP), which can be a standalone device or built into a router or switch
When would WIFI be preferred over Bluetooth?
High speed data transfer is required
Long range communication is required
Many devices are needed to be connected at the same time
What are the advantages of WIFI?
Portability - Easy to move around, location is only limited by range
Cost - Less expensive to setup and add new devices
Compatibility - Most devices are manufactured with a built in Wi-Fi adapter
What are the disadvantages of WIFI?
Speed - Slower data transfer than Ethernet
Security - Less secure than Ethernet
Range - Relies on signal strength to the WAP, signals can be obstructed (up to 100m)
What is Bluetooth?
Bluetooth is another common standard for wireless networks
Bluetooth is common in most homes and offices to connect devices such as headphones, controllers, keyboards & mice
Bluetooth is used typically for a direct connection between two devices
When two devices pair, they both exchange a cryptographic key
The keys are used to generate a secret shared key which is used to encrypt the data between the two devices and create a Wireless Personal Area Network (WPAN)
Connected devices continuously change their transmitting frequency between 79 different channels to avoid interference and improve the reliability of the connection
This is known as the frequency hopping spread spectrum (FHSS)
What are the advantages of Bluetooth?
Compatibility - Ideal for personal devices and ad-hoc connections
Power - Very low power consumption
What are the disadvantages of Bluetooth?
Speed - Very slow transfer speeds
Security - Data can be intercepted by anyone in range
Range - Short range (30m)
What are the differences between Bluetooth and Wifi?
Bluetooth: 7 connections, 30 metres maximum range, 3 Mbytes maximum transfer speed
WIFI: 30 connections, 100 metres maximum range, 75 Mbytes maximum transfer speed
What is GPS?
Global Positioning System (GPS) is a satellite system used to track the exact location of an object
GPS uses orbiting satellites to receive, amplify and transmit signals
Radio frequencies are used to communicate between satellites and ground stations
GPS requires a direct line of sight
What are the advantages of GPS?
Wide coverage area
Real-time data transmission
Improved communication in remote locations
Accurate location tracking
What are the disadvantages of GPS?
Expensive setup and maintenance
Signal interference due to weather or obstacles
Limited bandwidth and capacity
Privacy concerns and potential for Surveillance
What is 3G and 4G?
3G and 4G are references to the 3rd and 4th generation of mobile data networks
They provide mobile devices with wireless access to the internet
Each generation has a faster transfer rate and an improved capacity for more users
3G - 256 Kbps (kilobits per second)
4G - 100+ Mbps (megabits per second)
The current generation (5G) has even faster speeds and lower latency
What is infra-red?
Infra-red is a wireless communication method used to transfer very small amounts of data to a device in direct line of sight
Uses light waves which can cause:
Walls or obstacles to block the signal
Sunlight to affect the signal
It is a reliable and cost effective solution for many short-range wireless communication needs
When is Infra-red commonly used?
Televisions
Audio receivers
Home entertainment equipment etc.
What is NFC?
Near field communication (NFC) is a subset of RFID which allows communication between two devices in very close proximity
NFC can be either:
Passive - uses energy from the reader
Active - has it’s own power source
Smartphones use active NFC to allow contactless payments by tapping a smartphone on a reader
Smartphones can also exchange data using NFC by tapping together (usually back to back)
What are the advantages of NFC?
Convenient
Secure
Very fast
Low power consumption
What are the disadvantages of NFC?
Limited range
Slow data transfer rate (not suitable for transferring large files)
Compatibility
What is bandwidth?
Bandwidth is the amount of data that can be carried by a connection in one second
Measured in bits per second (bit rate)
A smaller bandwidth means that less data can be sent and the network can slow down, potentially to the point of becoming unusable