Redactron Corporation

Morton B Herman

Francis C Marino

A display system which has a source of blocks of codes representing characters to be displayed and a display device which converts the blocks of codes to lines of visually displayed characters is provided with a buffer memory which connects the source to the display device. The buffer memory includes a random access memory (RAM) with addressed registers for storing the codes and an address generator in the form of a counter. When a block of codes is transferred from the source to the buffer memory, the counter is initialized and as each code is transmitted to the buffer memory the counter is incremented. Each time the block of codes is transferred from the buffer memory to the display device the counter is again initialized and with the reading of each code from the memory the counter is again incremented. The buffer memory includes two identical RAMs and is controlled such that while one RAM is being loaded the other RAM is being read.

Display device with variable capacity buffer memory

In a keyboard having two depressable key switches which receive pulses of a first given width and transmit in response thereto pulses whose width is a function of the mechanical travel of the key switch, the travel of the key switches is detected by feeding a pulse of a first given width alternately to the key switches, sensing for the width of pulses transmitted by the key switches in response to receipt of the pulses of first given width. When the width of a pulse transmitted by one of the key switches in response to the receipt of one of the pulses of the first given width exceeds a second given width which is less than the first given width, there is fed a series of the pulses of first given width only to such one key switch and none of the pulses to the other of the key switches. Then, there is indicated that such one key switch has been reliably depressed if for a given period of time all the pulses transmitted by such one key switch in response to the series of pulses have at least the second given width.

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Queens Village, NY, United States of America

Morton B Herman