Abstract: An external defibrillator system for assisting manual delivery of chest compressions and ventilations to a patient by a rescuer as cardiopulmonary resuscitation (CPR) includes a speaker, and a processor, memory, and associated circuitry coupled to the speaker. The processor is configured to initiate prompting for the chest compressions and the ventilations manually delivered to the patient by the rescuer as CPR, control the speaker to generate first auditory cues for the chest compressions, and control the speaker to generate second auditory cues for the ventilations with a different sound than the first auditory cues for the chest compressions. The first auditory cues and the second auditory cues assist the rescuer in timing the delivery of the chest compressions and the ventilations.