How to set alarm on G-Shock G-100 / Casio 5158

Before using this guide, we recommend:

• Download official G-100 Manual →
• Watch official 5158 G-100 Manual Online →

All settings are clearly explained and understandable.

1. In the Alarm Mode, hold down B for about two seconds, until “ADJ” and then the hour digits flash on the display. Keep B depressed until the hour digits fl ash.
2. Press C to increase the setting. Holding down C changes the current setting at high speed.
3. Press B to change the selection in the above sequence.

• The format (12-hour and 24-hour) of the alarm time matches the format you select for normal timekeeping.
• When setting the alarm time using the 12-hour format, take care to set the time correctly as morning or afternoon.
• If you do not operate any button for a few minutes while a selection is fl ashing, the flashing stops and the watch goes back to the Alarm Mode automatically.
• The alarm is turned on automatically whenever you change the alarm time setting.

To stop the alarm

In any mode, press any button to stop the alarm after it starts to sound.

To switch the daily alarm on and off

In the Alarm Mode, press B to turn the daily alarm on and off.

To test the alarm

Hold down C while in the any mode to sound the alarm.