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SCP sighs theatrically when confronted with laser-equipped hand-held barcode-readers, becuase we are Much More Fond of various punch-tape readers:

Here are eight basic techniques now in use to read the digital information from punched paper or plastic tapes. Three different mediums are used to sense a hole in the tape: air, mechanical fingers, and light. Only the method of producing an output signal that represents the presence of a hole is shown - design details of complete reading stations or additional electronics that may be necessary have been omitted