necessity of providing power lines between a remote stationary power source and the movable carriage the opk switch 27 is a three position switch which an operator may move from a first position o in which the control system is turned off to a second position p in which the system is conditioned for reading the program card 30 into the memory 32 from the second to a third position k in which the system is conditioned for knitting a programmed design and from the third position back to the off position the card which may be best seen in fig2 is used to instruct the needle selector control system concerning a design which is to be produced on the knitting machine as shown the card includes mutually perpendicular lines which define rectangles 44 that extend in numbered columns 1 through 32 and numbered rows 1 through 16 the card also includes a row of strobe markings 46 which are provided for a purpose hereinafter explained an operator indicates the design unit he wishes produced such as that shown in fig2 by darkening selected ones of the rectangles 44 on the card with a pencil or other marker preferably one leaving an erasable mark and then feeds the card left end first through the reader the reader includes a paired light emitting diode led and phototransistor for each of the numbered rows on the card and for the row of strobe markings 46 in fig3 which shows the control system for the needle selectors 24 and 26 the led phototransistor pairs 48r 1 50r 1 52r 16 54r 16 and 56r s 58r s have been illustrated for row 1 row 16 and the strobe markings respectively and it is to.