Casio 5161 User guide

Firstly, make sure it is in the Timekeeping Mode.
DST Setting Module : 5161
Holding down (B) for at least two
seconds at any time will return
directly to the Timekeeping Mode.
2.
In the Timekeeping Mode,
hold down (A) button for
about three seconds until
ADJ appears on the display.
1.
<Timekeeping Mode Screen>
Press (B) button twice to
enter the Daylight Saving
Time setting mode.

4.
Use (C) button to toggle ON, OFF and AUTO.
OFF
ON
AUTO
3.
Press (A) button to return
to the Timekeeping Mode.