Casio IT-2000W Technical Reference Manual page 93

Transition of Backlight Control Methods
The concept of ABC lies in automating user operations. However, automatic control depends on the
illumination sensor. It cannot be perfect because various types of light, sunlight or room light for
example, may be incident to the sensor. Consequently, this requires manual ON/OFF control even if
under ABC control. This leads to a further problem wherein the user may forget to turn it on or off.
To avoid these problems this system employs the following rules for transition between ABC,
manual operation (ON function/OFF function), and ABO.
OFF
ABC OFF
ABO time or
OFF function
ON function
ABC ON
ABC Control
Fig. 6.6
93
OFF function
OFF function
or ABO time
ON