Display unit comprising input means for an oscillating signal (having an amplitude and a frequency, i.e. chest compression signal from a CPR session), a first indicator adapted to be activated when the amplitude reaches a maximum value, a second indicator adapted to be activated when the amplitude reaches a minimum value, a third indicator adapted to be activated partially or fully depending on amplitude, a fourth indicator adapted to be activated by a secondary signal derived from the input signal's frequency and a fifth indicator adapted to be activated when there is no input signal during a predetermined period of time. The first and the second indicators have different states (brightness) depending on the number of occurrences of a maximum respectively minimum amplitude over a period of time. The fourth indicator comprises a central zone adapted to be activated when the signal's frequency lies within a maximum and minimum value and two sides zones activated when the signal frequency exceeds the maximum and minimum value, respectively.
