This punched card decoder helps you read IBM cards in the EBCDIC encoding. Possibly you found the decoder in its holder and followed a QR code to get here: otherwise, follow the instructions in "How to make" to make a card.
The sample punch card on the instruction side has every character punched, and contains the same information as the table. The table, however, can be used with a simple algorithm to look up characters quickly. Refer to the sample punch card to test your understanding of the table.
Read a punched code from left to right, like a line of ordinary text. If you're lucky, a line of characters is printed at the top of the card (like the punched card on the instruction side of the decoder.) In that case you're done; otherwise, continue.
The top three rows are groups 12, 11, 10. The remaining rows are numbered 1 through 9, which I'll refer to as digits.
No digits or groups punched: encodes a space (ASCII 32)
1 digit or group punched: look up the group or digit label on the far left and find the character in the first column of the table. Digits code for themselves. The numeral zero is coded with group 10, and the minus sign with 11.
1 digit and one group punched: Look up the group label on the left side of the horizontal axis and the digit label on the vertical axis and find an uppercase letter or slash. For instance, the letter "M" has 11 and 4 punched.
8 punched and one other digit: See the column at the left of the "with 8 punched" area. The plus sign is coded with by punching 2 and 6.
8, another cell, and a group punched: look up the character at the intersection of the group and digit on the right side of the table labeled "with 8 punched"
If this card is missing from its holder or if you'd like one of your own, make one.
Print the two sides (instruction and table) of the punchcard decoder on two sides of a 4"x6" card with weight between 45 and 65 lbs. Canon Matte Photo Paper is good if you have an inkjet printer. If applicable, print instructions on the coated (brighter) side of the paper.
At public punched card displays, the holder communicates that the decoder is a public affordance.
If you wish to make a holder, use a heavy 5x7" card such as 60 lb Polar Matte and print the Holder Image scaled to fit the card on the coated side of the paper.
Cut away the bottom two inches of the holder. of the card. Clean the surface with soap and hot water or with isopropyl alcohol. Attach the holder to the wall with strips of Scotch Magic™ tape on the left, right and bottom of the holder with the tape straddling the front side of the paper and the surface.
Install decoder in holder.
[DOWNLOAD INSTRUCTION SIDE IMAGE]
It take about 8 ¢ worth of materials to make a punchcard decoder. The punchcard decoder is © 2021 by Paul Houle ph18@cornell.edu; who grants you the non-exclusive right to use the instruction and table images as directed to manufacture punched card decoders.
DO NOT FOLD, SPINDLE, OR MUTILATE