A cardiac pacemaker, defibrillator, or other programmable medical device (25) includes a source unit (15) and a collection unit (20). The source unit (15) has a check data unit (40) generating at least one check datum for control data for the medical device (25), and a transmitting unit (45) transmitting the control data and the check datum to the collection unit (20). The collection unit (20) has a storage unit (65) storing the control data, a check unit (70) checking the integrity of the control data using the check datum, and a transmitting unit (75) transmitting the control data to a programmable control unit (80) of the medical device (25) only if the integrity of the control data is established by the check unit (70). The control unit (80) of the medical device (25) controls the functions of the medical device (20) on the basis of the transmitted control data.
