**Recall:**Computers communicate using binary- Therefore, computers do NOT process information using characters (e.g. letters).
- Each letter or character has a number representation that the computer uses to refer to the character.
**ASCII:**American Standard Code for Information Interchange- ASCII is a code for representing English characters as numbers.
- The ASCII numbers range from 0 to 255, each representing a character.
*Numbers 0-32 are set aside for communications and printer control**Numbers 33-127 are standard characters**Numbers 128-255 are**“**extended**”**characters, or those not found on the keyboard.*- Humans process information in decimal and ASCII
- Therefore, when communicating with a computer, the computer will translate the information from ASCII to binary for us! (and also binary to ASCII)
- Recall
- When converting binary to decimal, binary numbers have a place value of base 2.
- That is

^{· }2^{7}2^{6}2^{5}2^{4}2^{3}2^{2}2^{1}2^{0}

^{ }

^{o }^{or}

^{ }

^{· }^{128 64 32 16 8 4 2 1}

^{ }

**Recall:**- Convert the following binary numbers to decimal numbers

- 00000101
- 00001000
- 01110101
- 01010001

- Notice: All the binary numbers are 8 digits long.

- Each byte in memory can hold an ASCII character.
- Each byte holds 8 bits
- Each bit can be represented by a 1 or 0

- Therefore, each byte can hold an ASCII character that is composed of 8 bits.

**Recall:**Memory can be thought of an array of boxes that holds a single byte of information.

**Solve:**- Convert the following binary numbers to ASCII characters
- 0111010101010001

**Solution**:**Step 1:**- Break apart the sequence into 8 bit (1 byte) sections to decode
- 111010101010001=1110101 and 0101000

**Note:**because 1110101 is seven digits and eight is needed, simply add a 0 to the front: 01110101

**Step 2:**- Convert each 8 bit sections to decimal numbers
- 01110101 = 117
- 01010001 = 81

- Convert each 8 bit sections to decimal numbers

**Step 3:**- Convert decimals to ASCII characters (by looking it up to the table)
- 117 = u
- 81 = Q

- Convert decimals to ASCII characters (by looking it up to the table)

- Therefore, 0111010101010001 = uQ

**Recall:**

- The ASCII representation for the letter ‘w’ is 119
_{10}. What is the ASCII representation for the letter ‘w’ in binary form?

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