Abstract: A card reader system providing for a plurality of card reader units to be interfaced commonly to a single central processing unit, each card reader unit having an interface assembly wholly contained within the card reader electronics package and providing for Hollerith to ASCII conversion, retransmission of card data as often as requested, and suppression of trailing zeros in the transmitted card data. Each interface assembly provides for the generation and transmission of status signals upon the occurrence of predetermined card reader conditions. Means are provided in each card reader for receiving address characters from the CPU whereby each respective card reader is selectively enabled or disenabled from communicating with the CPU depending upon whether or not it has been properly addressed.