TI-59 magnetic card
The TI-59 was a programmable calculator from Texas Instruments which was available from 1977 through 1983. It supported the ability to load and save programs using a magnetic-stripe card reader. The TI-58 model was also available at the same time with similar programming features but no card reader.
If you ran out of magnetic cards for it, it was apparently possible to make new ones by cutting up floppy disks.
The card reader used a four-track head designed to function at a speed between 2.0 and 2.5 inches per second. Track one is closest to the edge of the card. The write signal is a square wave of +/- 1.5 V.