ACCUMULATOR FOR A KEY ENTRY DEVICE

This specification describes an accumulator for a key entry device which has a shift register buffer memory that holds a character entered from a keyboard. The accumulator performs computation on the data on punch cards used by the key entry device. These computations can include the addition or subtraction of data in two or more numeric fields to be punched on the same card to provide a total that is punched out in a third numeric field on that same card or can include the computation of a running or hash total of the same numeric field on a number of different cards forming a group or batch of cards. The accumulator comprises a counter for converting the ten numeric bits of the serial Hollerith code used in punching data onto cards to four parallel BCD bits used in performing addition or subtraction with the data, a buffer for storing the accumulated total in BCD and a plurality of single bit adders and registers for performing the addition on data to be added to or subtracted from the accumulated total.