Reading a punch card proves to be incredibly difficult once you actually begin looking at it. First, when reading a punch card, be sure it is actually facing the right way and not upside down - if it is you will soon come to find out that the language is impossible to understand. The notch in the card should be at the top left hand corner.
Once you have completed this trying task...
Read the card in the following manner- vertically (up and down not side to side - down 80 columns)
1) If the card has only one punch, in a certain number, that represents the actual number which is being represented. So, if you have the number 4, that would be punched out of the card going down vertically. If the number was 18, row 1 would have 1 punched out of it and row 2 would have 8 punched out of it.
2) Then, it comes time to read a punch card with actual words and symbols. The symbols were represented with multiple digits, for example, the group which I worked with discovered that a comma was represented by the 0, 3, and 8 being punched out and the period was indicated by a punched out the top above the 0, 3 and 8. Symbols always have 3 punches and letters are represented by 2. This make it easy to distinguish if you are reading a number, letter, or symbol.
3) When reading the letters, it can be difficult to tell which is which. We found that the letters in the first part of the alphabet (A-N) were represented within the top half of columns 1-80 whilst the remaining 13 letters of the alphabet (M-Z) were shown in the bottom half of columns 1-80.
4) The punch card is set up so that the order goes from 12-9. (12, 11, 0, 1, ....9) where the top two rows (12 and 11) are zone rows and the remaining are the numeric rows. This makes up the alphabet. For example if 12 and 1 are punched out the letter A is represented.
5) The punch card is able to have 64 separate punches each representing a different symbol number or letter. This allows many combination's with the alphabet only being 26 letters.
6) The below website (2nd one) demonstrates the alphabet for the punch card and what the symbols are. It shows that B = 12 and 2, C= 12 and 3, and that D= 12 and 4 (etc). Once you have reached the limit for the combination's which can be made with 12 (which would be 12 and 9 letter I) the use of number 11 would start i.e. 11 and 1 would be J and so on...
It is fairly simple once it is understood! Use the websites below to help, mainly the second one. The second website provides excellent information on how to read a punch card.
References...
http://en.wikipedia.org/wiki/Punched_card#Card_formats
http://www.cs.uiowa.edu/~jones/cards/codes.html
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