Binary Number System: Representations

ASCII Characters

The ASCII character code is a somewhat arbitrary system which places each typed character on the computer's keyboard into a 7 (or 8) bit sequence. For example, consider the bits:

010000012 = 4116
What character does this represent? It turns out that inspection of an ASCII table shows us that this is the uppercase "A" character. Why isn't it the lowercase "t" character? Well, simply, because it isn't. Someone had to agree on a code and put it into service. This is that standard code. There are some sensible qualities to the code. For example, while it's not clear why "A" should be code 4116, it makes sense that code 4216 is "B" and that code 4316 is "C", etc. Not all standard systems are organized that way. For example the EBCDIC system once used by IBM has gaps between the letters I and J and between R and S. Go figure.

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