Nat 4/5 Computing Science Interfaces Computer Systems Nat 4/5 Computing Science Interfaces

Nat 4/5 Interfaces Hardware and software that allows the processor to communicate with peripherals Peripherals – devices that are connected to the computer e.g. Input devices Output devices Storage devices

Functions of an interface Nat 4/5 Functions of an interface An interface allows devices that work differently to communicate Differences in operation include:- Transferring data at a different speed Using data that is in a different format

Functions of an interface – data storage Devices may work at different speeds from the processor A keyboard or printer may transfer data more slowly than the processor To solve this problem an interface can store data temporarily so that the processor and device can communicate

Analogue and Digital data formats Nat 4/5 Analogue and Digital data formats Computers use digital signals 0 and 1 are used to represent data A digital signal could look like:- An analogue signal varies continuously between two limits Sound, light, temperature are analogue

Functions of an interface – data format conversion Devices may use data that is in a different format from the processor An interfaces solves this problem by :- converting digital data to analogue data or Converting analogue data to digital data

Functions of an interface - Digital to analogue conversion E.g. when playing music a processor uses an MP3 file which stores digital data (1’s and 0’s) but the speakers output analogue sound An interface can convert digital data to analogue data Interface

Functions of an interface - Analogue to digital conversion An interface can convert analogue data to digital data e.g. when using a microphone or scanning an image Interface

More Examples of Data Format Conversion Interface carries out digital to analogue conversion Interface carries out analogue to digital

Types of interface : USB 2 USB = Universal Serial Bus - standardised the connection of devices – many devices use USB Used to connect:- mouse, keyboard, printer, card reader, etc

Types of interface : USB 3 10 times faster than USB 2 Used when very fast access to data is required e.g streaming HD movies making a backing up of an internal hard drive to an external hard drive

Types of interface : Thunderbolt Thunderbolt – high speed interface Connects devices to the computer e.g. HD camera, keyboard, printer, monitor, etc

Types of interface : IEEE 1394 / Firewire (Apple) / i.Llink (Sony) High speed connections All have similar uses to USB Often used by digital video cameras

Types of interface - SATA Connects motherboard to hard drive or optical drive

Types of interface - Ethernet To connect a computer to a Local Area Network a computer must be fitted with a Network Interface Card (NIC) – this is normally installed by the manufacturer The Network Interface Card uses an Ethernet interface

Types of interface – Wireless network interface To use a wireless network a computer must be fitted with a Wireless Network Interface Card (WNIC) Wireless interfaces include:- Bluetooth WiFi

Questions What is an interface? What is a peripheral? Briefly describe the function of an interface. What job does an interface carry out when a peripheral transfers data at a different speed from the processor?

More questions Describe digital data. Describe analogue data. Describe an example of when Analogue to Digital conversion is carried out by and interface. Describe an example of when Digital to Analogue conversion is carried out by and interface. Name a common type of interface.