The punches are interpreted across the top line of the card; this is a feature of the key punch and it works as long as there's a good ribbon. OS JCL Job-card fields are preprinted on the card. Columns 73-80 are reserved for sequence numbers, which can be used by a sorter to put a deck back in order after it has been dropped.
Here is a card punched on keypunch that either had no interpreter, or a broken one, or whose ribbon was dry. The diagonal cut on the upper left facilitates proper orientation of the card (if the card is fed into the reader upside down or face down the data will be misinterpreted). When all the cards in a deck of the corner cut, misoriented cards will stick out.
Here's another customized card (without punches), this one from the University of Karlsruhe (Germany) Computer Center, courtesy of Michael Hartmann, Technische Universität München:
|Columbia University Computing History||Frank da Cruz / email@example.com||This page created: January 2001||Last update: 28 December 2021|