When all 5 LEDs are on simultaneously, the unit is charged and ready for use.
The device is in charging mode when 1 to 5 LEDs are on alternately (from left to right).
When the first LED (led1) is on steadily, the device is in connection with the phone.
The device records the signals with the fast blinking of the second LED (led2).
When the third LED (led3) is on steadily and operates typically with the second LED, the device is in ECG validation mode.