Types of Digital Communications (Edexcel IGCSE ICT): Flashcards

A wired connection is faster, with higher bandwidth and lower latency, gives a more stable connection, suffers less interference, is more secure, and needs no password.

The user can move around while transferring data, does not have to waste time finding and connecting cables, avoids the cost of cables, and there are no trailing wires to create a hazard.

Wi-Fi connects devices to a LAN, Bluetooth connects two devices over very short distances, infra-red (IR) transmits tiny amounts of data over very short distances, NFC uses close proximity RFID, and 4G and 5G provide internet access to mobile devices.

A local area network is a network covering a small geographical area (under 1 mile), where all of the hardware is owned by the company, organisation or household using it.

A LAN uses unshielded twisted pair (UTP) cable, fibre optic cable or wireless connections (Wi-Fi).

A LAN allows centralised management of updates, backups and software installations, lets devices be secured with firewalls and antivirus software, lets users share resources such as printers, and lets users collaborate and share files and folders.

If hardware fails the network may not function, networks are more prone to attacks than standalone computers, access can be slow depending on network traffic, and they require maintenance which can be costly.

A wide area network is a network covering a large geographical area (over 1 mile), made up of a collection of LANs joined together.

The computers on a WAN are connected via routers.

False.

On a WAN the connecting hardware is not all owned by the organisation using it — telephone lines, for example, are owned by telecommunication companies. On a LAN, all the hardware is owned by the user.

A WAN uses fibre optic cable, telephone lines and satellite.

A personal area network is a network used for the transmission of data between devices in close proximity, with a very short range of about 10 metres.

Bluetooth is the most widely used personal area network.

Typical devices are wireless headphones, mobile phones, tablets and laptops.

Tethering is when a host device shares its internet connection with other connected devices.

Tethering can be enabled or disabled as part of the mobile contract, and some network providers charge extra to use the feature.

Devices communicate with a hotspot or a wireless access point (WAP), which can be a standalone device or built into a router or switch.

Wi-Fi is preferred when high speed data transfer is required, when long range communication is required, and when many devices need to be connected at the same time.

Wi-Fi offers portability, since location is only limited by range, low cost to set up and add devices, and good compatibility, since most devices have a built-in Wi-Fi adapter.

Wi-Fi has slower data transfer than Ethernet, is less secure than Ethernet, and relies on signal strength to the WAP, so signals can be obstructed.

Bluetooth is typically used for a direct connection between two devices, such as headphones, controllers, keyboards and mice.

They exchange a cryptographic key, which is used to generate a secret shared key that encrypts the data between them, creating a Wireless Personal Area Network (WPAN).

Bluetooth is ideal for personal devices and ad-hoc connections and has very low power consumption, but it has very slow transfer speeds, data can be intercepted by anyone in range, and it has a short range.

Bluetooth has a maximum range of about 30 metres, while Wi-Fi reaches about 100 metres.

Bluetooth supports a maximum of 7 connections, while Wi-Fi supports up to 30.

Global Positioning System is a satellite system used to track the exact location of an object, using orbiting satellites to receive, amplify and transmit signals.

False.

GPS requires a direct line of sight, and its signal can suffer interference due to weather or obstacles.

GPS offers a wide coverage area, real-time data transmission, improved communication in remote locations and accurate location tracking, but it has expensive setup and maintenance, signal interference, limited bandwidth and raises privacy concerns.

They are the 3rd and 4th generations of mobile data networks, giving mobile devices wireless access to the internet; each generation has a faster transfer rate and improved capacity for more users.

Infra-red transfers very small amounts of data to a device in direct line of sight, and is commonly used in remotes to control televisions, audio receivers and home entertainment equipment.

Infra-red uses light waves, so walls or obstacles can block the signal and sunlight can affect it.

Passive NFC uses energy from the reader, while active NFC has its own power source — smartphones use active NFC for contactless payments.