In class today we learned how to decipher and read a punch card. Although they look intimidating a first, there I am going to explain step by step an easy way to read them.
A punch card can be defined a piece of paper that displays digital information by using a series of holes and corresponding numbers to represent numbers and words. For a better description and summary of the history and invention of the punch, please follow this link on Wikipedia: http://en.wikipedia.org/wiki/Punched_card
To start out, there are 12 lines altogether on your card that will help you decipher the corresponding number or letter that was typed.
The first two lines are blank (12 & 11) which helps to establish what letter is being typed or special character, followed by the number 0-9.
Numbers correspond directly to their number that is punched, basically numbers are easy to recognize. The letters of the alphabet get a little bit trickier.
If a hole is punched on the 12th, along with an additional punch, that is referring to the first 9 letters of the alphabet. The 11th line corresponds with the second sets of 9 letters, and line 0 corresponds with the last set of 9.
For visual a good visual aid, follow this link http://www.cs.uiowa.edu/~jones/cards/codes.html.
ABCDEFGHI= 12TH line and corresponding number
JKLMNOPQR= 11TH line and corresponding number
STUVWXYZ= Line 0 and corresponding number
- Single punches= number
- 2 punches= letter
- 3 punches= special character
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