Abstract: A transaction system comprises a plurality of transaction units each for performing a respective type of transaction. The units are interconnected via a serial link, and there is a common controller which has respective protected memory areas storing Java code for controlling the respective units.

Abstract: An apparatus and method of validating coins involves taking two independent measurements of the tested item, and determining whether both measurements lie within respective ranges for a particular coin type, the range for at least one of the measurements being dependent upon at least one other measurement.

Abstract: A method of testing coins comprising at least taking two measurements of an unknown coin: and accepting said unknown coin as corresponding to a first coin type if the point defined by the measurements lies, in the space defined by the axes of the measurements, on a first side of a discriminant surface at which the Mahalanobis distances of the centers of the distribution of said first coin type and a second coin type are in a predetermined relationship, characterized in that said relationship corresponds (at least approximately) to equality of the sums of the respective Mahalanobis distances with respective predetermined constants at least one of which is non-zero.

Abstract: Coin validation apparatus comprising a coin path (2, 5, 6); an impact element (14) disposed in the coin path to be contacted by a coin (10); an impact transducer (8) arranged to generate an output signal in dependence on vibration of the impact element (14); and control means (7) for determining a coin parameter based on the output signal; characterised in that the impact element (14) is shaped to create multiple impacts with a passing coin (10).