functions: 1. three channel digital ecg machine with measurement 2.simultaneous 12 lead acquisition 3.multiple operation mode (manual/auto/european mode) 4.lcd to display operation status and ecg waveform 5.the wave-form is displaying synchronously on the lcd with 200 x65 dots 6.designed with a high-resolution thermal printer to print out ecg waveform, annotation as well related parameters for diagnosis reference. 7. digital isolation technology is adopted to minimize time/temperature drift of components so as to promote adaptability of the unit to circumstance. 8. digital filter for effective inhibition of baseline drift, interference, as well automatic position of baseline. 9.self-test upon powering on. 10. function of rhythm lead for observing abnormal ecg waveform & heart rate. 11. automatic measurement and interpretation of ecg waveform to relieve doctors from strain. 12. multiple print formats include 3-channel, 2-channel, 1-channel, and particularly the one that combines 3-channel (for lead i-avf) and 2-channel (for v1- v 6). 13. ac/rechargeable battery for supporting continuous examination when ac power supply is unavailable. for battery operation, ecg-903 is equipped with a charger system for battery capacity management and protection itself from excessive discharge. 14. safety level corresponds to class i, type cf.