A piece of scrip is engraved or printed with groups of patterns which can be sensed by a validator for scrip and one of those groups of patterns will define a code which will permit that piece of scrip to be accepted only by a scrip validator or by scrip validators which have that same code stored therein. Two additional groups of patterns define codes which can cause that scrip validator or those scrip validators to automatically respond to the codes stored therein to actuate price-determining relays within a vending machine. Each pattern is formed by a number of spaced parallel lines, and the various patterns on a piece of scrip can be given different identities merely by changing the spacing between the trailing edges of those spaced parallel lines. The patterns in each group of patterns will be sensed in a prescribed sequence, and the sequentially-sensed patterns in any of those groups of patterns can be given various identities. As a result, the scrip validator of the present invention can accept a piece of scrip which has a given number of patterns of specifically-different identities and yet reject a piece of scrip which has those same patterns arranged in a different sequence. In this way, the present invention makes it possible to use permutations, rather than mere combinations, of potentially-usable pattern identities, and thus makes it possible to use just fifteen specifically-different pattern identities to make thirty-two thousand seven hundred and sixty different pieces of scrip. The scrip validator of the present invention stores the codes, which correspond to the codes defined by the patterns on the piece of scrip, in serially-shifted shift registers; and, as each pattern on the piece of scrip is sensed by the scrip validator, the data within the shift registers is serially shifted a plurality of times. The identity of any given pattern can be determined by three signals; and, by utilizing serially-shifted shift registers which have seven or more stages, the present invention enables each shift register to store the pattern-identifying data for at least two patterns. In addition, the serial shifting of the shift registers permits the pattern-identifying data for the various patterns to be presented in fixed sequences. Moreover, by merely changing some of the connections to the input terminals of the shift registers, it is possible to change the codes stored within those shift registers. The frequency which identifies each pattern is sensed by the combination of a digital filter and a counter; and such a combination provides a strict test of the identification of each pattern because it requires the frequency which corresponds to the spacing of the trailing edges of the lines of that pattern to match the frequency of the digital filter, and it also requires that pattern to have a minimum number of lines which have that same spacing.