After characterisation of the clinical expert's hand movement, a 6 dof probe holder robot will be designed according to the clinical needs; it will include rotations and linear displacements. Kinematics, dynamics behaviours and control laws will be developed. Force feedback control for a bilateral tele-operation architecture will be defined. Technique of ultrasound images acquisition via frame grabbing will be developed. Images compression techniques will be tested. Two solutions will be proposed depending on the examination phase : fast compression method when expert researches for a specific organ and an accurate compression method (wavelet) during the pre-diagnosis phase. An audio-video conference system will be used for the environmental data transmission. The project foresees three scenarios for data transmission : terrestrial link (ISDN, GPRS..), 2.5 and 3G mobile and a mobile communication system from the field of operation with an omni-di! rectional antenna (the 56 Kbps rate will allow clinical data access or images transfer); A fixed dish terminal (up to 384 Kbps operation for full motion video). At the master station, located at the expert centre, an interface with the communication system and image sequences decoder will be developed to allow high quality visualisation of ultrasound images. This interface will integrate: ultrasound images sequences, a view of the examined area provided by a camera and an audio/video conference. A virtual reality environment associated with a fictive probe will be designed: current technologies will be investigated, the most suitable will be selected for the application. Three slave and masters stations will be made. The slave stations, located in secondary hospitals, will integrate the probe-holder robot, current technologies will be investigated, the most suitable will be selected for the application. They will be used for the technical and clinical validation of the OTELO ! project.