page_title: Punched card
section_title: IBM 80-column punched card format and character codes
hierarchical_section_title: Punched card / Card formats / IBM 80-column punched card format and character codes
caption_attribution_description: English: Description: 5081 data processing card containing a line of DOS JCL code. The code reads: //STEP2 EXEC PROC=SLINK,TESTPGM=DADK,ACCT=DADK Source: Scanned image of my personal property Date: 10 November 2006 Author: Dick Kutz (Dick107) 04:30, 11 November 2006 (UTC)) Permission: GFDL Other versions: None
context_page_description: A punched card or punch card is a piece of stiff paper that can be used to contain digital data represented by the presence or absence of holes in predefined positions. Digital data can be used for data processing applications or used to directly control automated machinery.
  Punched cards were widely used through much of the 20th century in the data processing industry, where specialized and increasingly complex unit record machines, organized into semiautomatic data processing systems, used punched cards for data input, output, and storage. The IBM 12-row/80-column punched card format came to dominate the industry. Many early digital computers used punched cards as the primary medium for input of both computer programs and data.
  While punched cards are now obsolete as a storage medium, as of 2012, some voting machines still use punched cards to record votes.
context_section_description: By the late 1920s customers wanted to store more data on each punched card. Thomas J. Watson Sr., IBM’s head, asked two of his top inventors, Clair D. Lake and J. Royden Pierce, to independently develop ways to increase data capacity without increasing the size of the punched card. Pierce wanted to keep round holes and 45 columns, but allow each column to store more data. Lake suggested rectangular holes, which could be spaced more tightly, allowing 80 columns per punched card, thereby nearly doubling the capacity of the older format. Watson picked the latter solution, introduced as The IBM Card, in part because it was compatible with existing tabulator designs and in part because it could be protected by patents and give the company a distinctive advantage.
  This IBM card format, introduced in 1928,
  has rectangular holes, 80 columns, and 12 rows. Card size is exactly ​7 ³⁄₈ by ​3 ¹⁄₄ inches (187.325 mm × 82.55 mm). The cards are made of smooth stock, 0.007 inches (180 μm) thick. There are about 143 cards to the inch (56/cm). In 1964, IBM changed from square to round corners. They come typically in boxes of 2000 cards or as continuous form cards.  Continuous form cards could be both pre-numbered and pre-punched for document control (checks, for example).
  Initially designed to record responses to Yes–no questions, support for numeric, alphabetic and special characters was added through the use of columns and zones. The top three positions of a column are called zone punching positions, 12 (top), 11, and 0 (0 may be either a zone punch or a digit punch). For decimal data the lower ten positions are called digit punching positions, 0 (top) through 9. An arithmetic sign can be specified for a decimal field by overpunching the field's rightmost column with a zone punch: 12 for plus, 11 for minus (CR). For Pound sterling  pre-decimalization currency a penny column represents the values zero through eleven; 10 (top), 11, then 0 through 9 as above. An arithmetic sign can be punched in the adjacent shilling column. Zone punches had other uses in processing, such as indicating a master card.
      _______________________________________________
     / &-0123456789ABCDEFGHIJKLMNOPQR/STUVWXYZ
  12|  x           xxxxxxxxx
  11|   x                   xxxxxxxxx
   0|    x                           xxxxxxxxx
   1|     x        x        x        x
   2|      x        x        x        x
   3|       x        x        x        x
   4|        x        x        x        x
   5|         x        x        x        x
   6|          x        x        x        x
   7|           x        x        x        x
   8|            x        x        x        x
   9|             x        x        x        x
    |________________________________________________
  
  　Reference: Note: The 11 and 12 zones were also called the X and Y zones, respectively.
  In 1931 IBM began introducing upper-case letters and special characters (Powers-Samas had developed the first commercial alphabetic punched card representation in 1921). The 26 letters have two punches (zone [12,11,0] + digit [1–9]). The languages of Germany, Sweden, Denmark, Norway, Spain, Portugal and Finland require up to three additional letters; their punching is not shown here. Most special characters have two or three punches (zone [12,11,0, or none] + digit [2–7] + 8); a few special characters were exceptions: "&" is 12 only, "-" is 11 only, and "/" is 0 + 1). The Space character has no punches.  The information represented in a column by a combination of zones [12, 11, 0] and digits [0–9] is dependent on the use of that column.  For example, the combination "12-1" is the letter "A" in an alphabetic column, a plus signed digit "1" in a signed numeric column, or an unsigned digit "1" in a column where the "12" has some other use. The introduction of EBCDIC in 1964 defined columns with as many as six punches (zones [12,11,0,8,9] + digit [1–7]). IBM and other manufacturers used many different 80-column card character encodings. A 1969 American National Standard defined the punches for 128 characters and was named the Hollerith Punched Car
caption: A 5081 card from a non-IBM manufacturer.
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