High resolution thermal printing array system. High frequency response reach to 150Hz Capable of printing continuous on channel trace and annotations including lead mark and such parameters as sensitivity, paper speed, and filter operation status. High resolution digital filter inhibits baseline drift without distorting ECG wave-form. One-touch operation able to enhance efficiency and relieve operating strain. Concept of floating input circuit meets IEC safety standard. Visual status due to light indicated touch-keys Rechargeable battery supporting more than 50 Patient examinations. Under the automatic mode, pressing key ?MODE? continuously can keep recording when abnormal lead is found.