1. A device for assessing a quality class of a device under test, comprising: a unit for detecting an acoustic non-voice test signal from the device under test; a unit for providing a stochastic Markov model including states and transitions between states on the basis of reference measurements of devices of known quality classes, wherein, in the stochastic Markov model, a single probability density distribution is associated with each state, and wherein several states have transitions from a common predecessor state; a unit for evaluating the acoustic non-voice test signal using the stochastic Markov model; and a unit for associating the device under test with a quality class based on the stochastic Markov model evaluation of the acoustic non-voice test signal.