Abstract: A Wearable Cardiac Defibrillator (WCD) system is configured to be worn by a patient who carries a mobile communication device. The mobile communication device has a user interface that is configured to enable the patient to enter wireless inputs. The WCD system includes a communication module that is configured to establish a local commlink with the mobile communication device. The mobile communication device can receive shock data from the WCD system after a shock is applied to the patient, can determine a location of the WCD system based on a location of the mobile communication device, and can transmit the shock data and the location data to a central call center of a remote assistance system. The central call center can enhance the operation of the WCD system by contacting the patient, contacting and emergency contact, and/or contacting a local emergency medical system (EMS).