unit 1 understanding computer systems - gcse...

Unit 1 Understanding computer systems:

How ICT can be used to meet business needs

Connecting devices



Connecting peripherals

Connecting to networks



Wired connections using USB or firewire and wireless connections can be used to connect peripherals.

Peripherals Peripherals are devices such as printers and scanners that are attached to a computer system but are not actually part of it.



USB (universal serial bus) is a standard way of connecting devices to each another. It allows fast transmission of data and is suitable for transferring data and files such as photographs from digital cameras to computers. USB has replaced older types of connection such as ‘parallel’ or ‘serial’ connections that were once used for connecting printers and scanners.

Connecting peripherals with USB



There are a number of different types of USB connector in use, depending on the device to be connected.

Types of USB connector Type B Type A

Micro (phone) USB

Type A Mini USB



Firewire is a very fast data transmission link similar to USB. It is used for transferring digital video, often from digital video cameras to computers systems.

However, firewire equipment can be expensive, so most devices now use USB connections instead.

Connecting peripherals with Firewire



Wireless connections allow devices to be moved about while still connected.

As there are no wires to be put in place, wireless connections are also used in buildings where the use of wires would not be suitable e.g. stately homes, or shops which often change their layouts and move the tills around.

Wireless technologies used to connect devices include:

Wi-Fi Bluetooth® Infrared

Connecting peripherals wirelessly



Wi-Fi is the registered trademark of the Wi-Fi Alliance but is now used to refer to a wireless network that connects devices together or to the internet.

Wi-Fi ‘hotspots’ are public access points to wireless networks, often in cafes or libraries, that allow users to connect wirelessly to the internet. Wi-Fi has a range of about 20m indoors from the access point.

Using public Wi-Fi ‘hotspots’ can mean that data is not safe. The connection may not be secure and others may be able to capture your data as it is transmitted.



Bluetooth® uses wireless technology to connect devices such as a keyboard and mouse to a computer. It is also uses to transfer data between hands-free headsets used in cars for mobile telephones.

Devices using Bluetooth® have to be ‘paired’ using the same passcode, which helps keeps data safe when it is being transferred.

Bluetooth®



Wi-Fi connections are used in homes to connect computing devices to the internet.

Businesses also use Wi-Fi in their premises to allow the connection of portable computing devices (e.g. smartphones and laptops).

Connecting to a wireless network

Wireless networks

To connect to a wireless network, devices must have a wireless network card. The card is usually built into smartphones, tablet computers, laptops and other portable devices. Wi-Fi connections can have a large bandwidth so large amounts of data can be transferred quickly.



Infrared connections are often used for the remote control of e.g. TV and DVD players.

Infra red connections can also be used to transfer data between e.g. a phone and a laptop. The devices need to be close to each other, making the transfer of data quite safe and not interfering with other devices.

Infrared



Wi-Fi connections are used in homes because they allow a number of devices to be easily and quickly connected to the internet using a single router.

Wireless networks at home



Wi-Fi connections are used in business premises because portable devices such as smartphones and tablet computers can then be connected to the company network and internet, and staff can move around while remaining connected.

Some businesses, e.g. cafés and hotels, can set up wireless networks for their customers and guests to use.

Wireless networks in business



Wireless networks use radio waves, which removes the expense and inconvenience of cables or wires.

The number of devices and the speed of transfer of data is determined by the bandwidth of the connection. High bandwidth allows for many devices to be connected at once, and the transfer of live video streams. Low bandwidth will mean that live video works poorly, or not at all, and downloads will be slow.

To connect to a wireless network, all devices must use the same SSID and the same type of security, and know the passwords or codes.

Connecting to a wireless network



Wireless networks each have a unique name, so that all connected devices can identify it. This is the SSID, or service set identifier, and must be used by all devices on the network so they can communicate with each other.

The SSID can be hidden, so that unauthorised users cannot even see that a network exists without first knowing its name.

SSID



Wireless networks are less secure than wired networks, so data is usually encrypted for transmission over the network.

Data is encrypted using an encryption key , often called the password or passcode, and every device on the network must use the same key and type of encryption.

There are several types of encryption used on wireless networks: WEP, WPA, WPA2, AES. All of these are used to make data more secure.

Security of wireless networks



Encryption is the scrambling of data to make it unreadable to anyone but those with the correct key. An encryption key is used to scramble and de-scramble data. Wireless networks use encryption to transfer data between devices. There are various methods of data encryption used on wireless networks: WEP: Wireless Equivalence Privacy was the first type of encryption but is now considered to be insecure compared to the later types and is no longer used. WPA and WPA2: Wi-Fi Protected Access is used to encrypt data on wireless networks. AES: the Advanced Encryption Standard is the basis of the encryption used.

Encryption

http://en.wikipedia.org/wiki/Wi-Fi_Protected_Access



http://en.wikipedia.org/wiki/Advanced_Encryption_Standard

unit 1 understanding computer systems - gcse...

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