Long ago, in the olden days before computers and E-mail there were Teletype Machines-- essentially two electric typewriters connected to each other by a wire.

Teletype machines needed a way to transmit text by sending electrical signals over wires. Since the only thing that could be transmitted was numbers, a standard representation of letters as numbers. was developed so all Teletypes could communicate with each other. This forms today's ASCII standard.

Non-printing control characters such as Line Feeds, Form Feeds, Tabs, Carrage Returns, Backspaces, Alarms such as a ringing bell and so on, were also needed to control the mechanical Teletype printer on the remote end.

The first version of ASCII only had 128 codes. (0-127) This was because that was all that were needed. 26 Upper Case Characters + 26 Lower Case Characters + 10 Digits, a few pieces of puntuation and a total of 32 control codes fit quite well into this 128 code limitation of the original standard.

Later, some manufacturers of Teletype equipment wanted to send characters that were not part of the 'Standard.' These included foreign language characters, drawing, math, scientific symbols and so on.

These manufacturers, (in particular, Wang and Commodore) independently developed their own proprietary use for codes from 128-255 (The "Upper Character Set.)

While their lower character sets adhered to the ASCII standard, their Upper Character sets were unique to their systems. Later these picked up the names of WANGSCII (Wang) and PETSCII (Commodore)

Today various fonts and 'Character Sets' make use of these upper characters in their own ways, so the only characters that can properly be called ASCII are the ones in the table below.

The chart below shows you the Hexadecimal and Decimal Numbers associated with the Standard ASCII Characters