Hello ,
The four leds is used to indicate which mode is on. This device is based on binary mode,
but how to read it : is led off means zero or one ? it is not very clear.
RTFM 
now
Hello ,
The four leds is used to indicate which mode is on. This device is based on binary mode,
but how to read it : is led off means zero or one ? it is not very clear.
RTFM now