This study was undertaken to determine whether using a model-telephone to simulate the emergency medical services activation component (EMSAC) during adult cardiopulmonary resuscitation (CPR) training practice would lead to better retention of this component during end-of-class assessment. In a prospective randomized manner, 233 medical professionals and lay-persons taking American Heart Association (AHA) CPR classes were evaluated for EMSAC retention during CPR skills performance at the end of class. During the assessment correct versus incorrect activation of EMS was noted. Subject response by age, exposure to previous CPR training, and medical professional or lay-person status was examined. Differences in results among instructors also were examined. Overall, those in the group using the model-telephone remembered to activate EMS correctly more frequently than those in the group not using the phone (69 vs 52%, P=0.009). The <30 age group was unaffected by the use of the phone (P=0.85). The group between 30 and 50 years of age did significantly better with the use of the phone (P=0.007), as did those 50 years of age and older (P=0.03). Previous CPR training did not affect the response (P=0.18). We conclude that use of the model-telephone improved EMSAC retention significantly overall except in the <30 year-old age group. We recommend using the model-telephone in future adult CPR classes.