Electronic apparatus for medical use, medical apparatus; patient monitoring, analysing and/or recording apparatus including digital apparatus; apparatus for investigating, monitoring, analysing, diagnosing and/or recording heart function and heart disorders, including portable apparatus; apparatus for investigating, monitoring, analysing, diagnosing and/or recording electrophysiological variables including variables relating to the nervous system, neurology, cardiology and physiology; apparatus for transmitting echocardiograms from an ultrasound machine to a personal computer; interface apparatus and sensors for monitoring patient variables including ECG (electrocardiogram), echocardiogram, EEG (electroencephalogram), EOG (electrooculogram), EMG (electromyogram), Sa02 (oxygen saturation), C02 (carbon dioxide), nasal air flow, patient movement including leg movement, thoracic and abdominal respiratory movement, heart rate, body temperature including rectal temperature, blood pressure, pH Level, oesophageal pressure, snoring noises, CPAP (continuous positive air pressure) mask pressure, CPAP mask air flow, CPAP titration; radiology imaging apparatus including remote imaging and transmitting apparatus; telemedicine apparatus especially for medical purposes including equipment for teleradiology, teleconsultation and tele-echo-cardiology; computer hardware and software especially for medical imaging including cardiology imaging, transmitting video and still images to a remote viewing system including an ultrasound viewing system; communication interface apparatus especially for medical purposes including modems, apparatus for interfacing ISDN (Integrated Systems Digital Network), PSTN (Public Switched Telephone Network), SCSI (Small Computer System Interface), Ethernet, HIS (Hospital Information System), RIS (Radiology Information System); apparatus for monitoring and/or displaying medical video and still images including images of the heart, ultrasound images and echocardiograms, including plotters and display monitors, video display monitors including CRT (Cathode Ray Tube), and flat panel displays including liquid crystal, TFT (Thin Film Transistor), and plasma displays; testing and/or calibrating apparatus for the above including apparatus for emulating physiological variables; parts and accessories thereof and therefor