Abstract: The subject of this disclosure is a Finite State Automaton (FSA) used as part of a term detector employed in a digital pattern search system (searcher). In particular the invention includes various advances in the art of FSA design which make the FSA practical for pattern recognition.Specifically, these advances minimize the amount of memory which is required in each FSA in performing pattern recognition, and allow a speed capability such that the searching can be performed at the rate at which a mass storage medium can supply data. The large amount of memory required and the low speed of processing in the prior state of the art made the use of an FSA impractical for most real applications.

Abstract: Bidirectional repeater circuits for bus-lines and the like are described which, when in idle condition, are capable of promptly transmitting binary data signals in either direction with amplification to restore wave form. A control signal is derived from each data signal during its transmission without imposing any time delay upon the transmission, and is used to disable temporarily signal transmission in the other direction. Thus, the repeater is self-contained in the sense of requiring no external control signal for controlling the direction of transmission. Capability for selectively disabling data transmission in both directions under external control can readily be incorporated in the circuits of the invention.