Security validator

In the field of security validators, slot acceptors have been known which transport paper offered as a valid security past a testing station. Previously known acceptors have been susceptible to defeat by mosaics, stringing, shocking, photocopy duplication, and the like. Additionally, known acceptors have operated in an analog mode, relying upon rudimentary test functions. The invention herein overcomes the problems of the prior art by presenting an acceptor having a note path (18) characterized by changes of direction (22, 24), and which is secured at each end by means of unique gate assemblies (78, 98). A plurality of sensors (148-152) are positioned along the note path and are controlled to take a multitude of data samples from the paper as it passes along the path. The data is digitized (236) and used for solving complex transforms, the results of which are compared against results obtained from known valid securities to determine the authenticity of the paper offered. Further, the system includes a unique antijamming technique of drive motor reversals, and an escrow feature which secures the paper once it has been determined to be authentic and before a vend has been made. Yet further, there is included a novel receptacle for receipt and return of paper offered to the acceptor, and a number of variations of anti-stringing devices (112, 114, 118, 130) which may be operatively positioned at the end of the note path.