1. A method of accepting money items, comprising: generating a money item signal that corresponds to a money item under test; determining a level of risk of a fraud attempt; determining a fraud attempt based on the level of risk; generating a transformed money item signal as a function of the level of risk and the money item signal in response to determining the fraud attempt; comparing the transformed money item signal to window limit values to generate a result; and accepting or rejecting the money item based on the result.