The invention concerns functions of an auxiliary device to multimedia equipment. These functions can be a function of physiological data processing, extended and/or uninterrupted operations with regard to monitored and processed data. Auxiliary functions are implemented by the auxiliary device and circuits, solutions can be physically placed in the original equipment or out of it but mechanically and electrically connected by it, it can form one compact unit. The parts, which are necessary to be changed during operation to get uninterrupted functions, are user friendly and simply exchangeable from usersaspect. One example of an auxiliary device is an ECG measurment device incorporated into a replacable battery back of a mobile phone.
