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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

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

10. 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

11. 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

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

13. 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

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

15. 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

16. 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

17. 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?

18. 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.