1. Information Support and Services
2.01 Understand how computers and high tech communication devices work.

2. Number Systems and Codes
Translate number systems and codes
Representations
Systems
Groupings
Translations
Codes

3. Translate number systems and codes
Why study number systems and codes?
Computers and smart devices are all based on circuits that work with only two states; on and off.
These states are represented by the binary numbers 0 and 1.
All data must be converted to binary code before being processed.

4. Translate number systems and codes
Representations
Data can be represented in two forms:
Analog
Digital
The majority of modern computers are digital devices.

5. Translate number systems and codes
Representations
Analog: Measuring or representing data by means of one or more physical properties that can express any value along a continuous scale.

6. Translate number systems and codes
Representations
Digital: Expressed in discrete numerical form, especially for use by a computer or other electronic device.

7. Translate number systems and codes
This course focuses on three number systems:
Decimal: The number system people use.
Binary: The number system most computers use.
Hexadecimal: A number system that is used to make binary numbers more compact.

8. Translate number systems and codes
Decimal:
Base 10
0,1,2,3,4,5,6,7,8,9

9. Translate number systems and codes
Decimal:
Place Weights 1 2 7 5
103
102
101
100
5x100 = 5
7x101 = 70
2x102 =
200
1x103 =
1,000
TOTAL
1,275
Any number raised to the power of zero is 1

10. Translate number systems and codes
Binary:
Base 2 1

11. Translate number systems and codes
Why Binary?
Computers are digital devices. They are made of millions of tiny transistors which are operated in one of two states – OFF (0) or ON (1)

12. Translate number systems and codes
Binary:
Place Weights 1 23 22 21 20
1x20 = 1
1x21 = 2
0x22 =
1x23 = 8
TOTAL 11
The only digits in a binary number are 0 & 1.
This is the decimal equivalent

13. Translate number systems and codes
Hexadecimal:
Base 16
We only use 10 digits, so letters are added.
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F

14. Translate number systems and codes
Why Hexadecimal?
Large binary numbers are difficult for humans to work with; hexadecimal is a more compact form.
It is quicker to convert between binary and hexadecimal than binary and decimal.
These are all the same number:
A 4 A 3
42,147

15. Translate number systems and codes
Hexadecimal:
Place Weights 2 A C
163
162
161
160
Cx1 = 12
Ax16 =
160
2x256=
512
0x4096=
TOTAL
684
This is the decimal equivalent

16. Translate number systems and codes
Where are some places hexadecimal numbers are commonly used?
The physical (MAC) address of a network card.
Color codes in html.

17. Translate number systems and codes
Binary Grouping
Bit
Nibble
Byte
BYTE (8 BITS) 1
Nibble (4 bits)
(One hex digit)
BIT

18. Translate number systems and codes
SI (International System) Units
The following metric prefixes are used to condense binary numbers:
Kilobit kb
Megabit Mb
Gigabit Gb
Terabit Tb
Kilobyte kB
Megabyte MB
Gigabyte GB
Terabyte TB
Typical Internet Speed = 1.5 Mb/s (Megabits per second)
Hard disk drive size= 1 TB (terabyte)

19. Translate number systems and codes
Conversions
It is often necessary to be able to perform the following conversions:
Decimal to Binary
Binary to Decimal
Decimal to Hexadecimal
Hexadecimal to Decimal
Binary to Hexadecimal
Hexadecimal to Binary

20. Translate number systems and codes
Remember:
A computer only operates on binary numbers!
Codes
American Standard Code for Information Interchange
ASCII (pronounced as-key)
A way of expressing text and other non-numerical characters in binary code.
Character
Hex
Binary A 41 a 61

21. Translate number systems and codes
ASCII
Text documents must be stored as numbers on the computer’s hard drive.
Text messages are transmitted as ones and zeros over the wireless network.

22. Translate number systems and codes
Unicode
The Unicode standard assigns codes to characters in many languages so a computer can recognize these characters.
Sample codes:
UTF-8
UTF-16
UTF-32
The number of characters represented increases as the UTF designation increases.

23. Translate number systems and codes
Unicode
The dominant scheme for internal processing and storage of text
UTF-8 is the most common Unicode encoding for HTML documents on the World Wide Web.
utf-8

24. Information Systems Websites
Open Book Project - Lessons In Electric Circuits -- Volume IV