A telecommunication system suitable for training of medical personnel in surgical theatres includes at least two input/output devices, including an eyeware framework such as head mounted device (HMD) 12 with an image acquisition device 14. The objectives of the input/output devices are operable in a passive mode, wherein the primary field of view are essentially transparent, thereby allowing the subject to perceive objects positioned upfront the input/output device and in an active mode, wherein the primary field of view portions are essentially opaque or opalesque, and whereby image and/or video data of the images acquired are generated and can be transmitted over a network between two such devices such that each device can generate data to be viewed on the other device. There may also be sound acquisition and reproduction devices such as a microphone (306, figure 3) and miniature speaker (250, figure 2g).