These were card readers with a mark reading mechanism for the HITAC 8000 Series. They could optically read data marked with pencil or homogeneous black ink on a card, and added an optical mark reading mechanism to card readers for the HITAC 8000 Series. The H-8233 and H-8238 were units for reading vertical mark data, and the different names were given according to processing speed.
H-8233: 750 cards/minute
H-8238: 1,500 cards/minut