Casio LDF-31 Watch

Important Information

Battery

If the display becomes dim or the backlight does not function, replace the battery at your nearest CASIO dealer or distributor. The battery included with your watch is for initial testing purposes and may have a shorter service life than a standard battery.

Water Resistance

Watches are classified by water resistance ratings (from I to V) according to their degree of protection against water. Refer to the table below to determine the rules for their use.

Notes for Corresponding Ratings

• Rating I: The watch is not water-resistant. Avoid all contact with moisture.
• Rating III: If the watch is exposed to salt water, rinse it thoroughly and dry it.
• Rating IV: If the watch is exposed to salt water, rinse it thoroughly and dry it.
• Rating V: The watch can be used for scuba diving (except for depths requiring helium-oxygen mixtures).

IMPORTANT!!!

For all watch categories, it is forbidden to:

• Press buttons underwater.
• Unscrew the crown underwater.

Care for Your Watch

The rubber gasket that protects the watch from water and dust should be replaced every 2-3 years. If water enters the watch, have it checked immediately by your nearest CASIO dealer or distributor. Do not expose the watch to extremely high or low temperatures. While the watch is designed for normal use, avoid rough handling and do not drop it. Do not fasten the strap too tightly. A finger should fit between your wrist and the strap. To clean the watch and strap, use a dry soft cloth or a soft cloth dampened with an aqueous solution of mild neutral detergent. Never use volatile agents (e.g., gasoline, solvents, aerosol sprays, etc.). When not using your watch, store it in a dry place. Avoid exposing the watch to gasoline, cleaning solvents, spray aerosols, adhesives, paint, etc. Chemical reactions caused by these materials can damage gaskets, the case, and the watch's finish. Some models feature silk-screened graphics on the strap. Be careful when cleaning these straps to avoid damaging the designs.

For Watches with Polymer Straps...

You may notice a white powdery substance on the strap. This substance is harmless to your skin or clothing and can be easily removed by wiping with a soft cloth. Exposure of the polymer strap to sweat or moisture, or storing it in high humidity conditions, can lead to damage, tearing, or cracking. To ensure a long service life for the polymer strap, wipe it clean of dirt and moisture with a soft cloth as often as possible.

Care for Fluorescent Cases and Bands

• Prolonged exposure to direct sunlight may cause the fluorescent color to gradually fade.
• Prolonged contact with moisture can cause the fluorescent color to gradually fade. If the watch surface gets wet, wipe it dry as soon as possible.
• Prolonged contact with a wet surface may cause the fluorescent color to discolor. Ensure the fluorescent surface is free of moisture and avoid contact with other surfaces.
• Rubbing a surface with fluorescent paint against another surface may transfer the fluorescent paint to that surface.

CASIO COMPUTER CO., LTD. is not responsible for any damage that may occur from the use of this watch, and accepts no claims from third parties.

Operating Modes

General Mode Switching

The illustration shows the watch in Timekeeping Mode.

Pressing [Button B] repeatedly cycles through the modes in the following sequence: Timekeeping Mode → Alarm Mode → Stopwatch Mode → Dual Time Mode → Timekeeping Mode.

Press [Button L] to turn on the illumination in any mode.

Timekeeping Mode

Pressing [Button C] in Timekeeping Mode cycles between 12/24 hour format. For the 12-hour format, the 'P' indicator shows PM, and for the 24-hour format, '24' is displayed.

Setting the Time and Date

1. Press [Button A] in Timekeeping Mode. The seconds will flash, indicating the start of setting.
2. Press [Button B] to move between setting items: Seconds → Hours → Minutes → Year → Month → Day → Seconds.
3. If seconds are flashing, press [Button C] to reset the seconds count to 00. If seconds are between 30 and 59, the minutes will increment by 1. If seconds are between 00 and 29, the minutes will not change.
4. Use [Button C] to change the values for minutes, etc. Holding the button down speeds up the change.
5. You can set the time for the year range 2000 to 2099.
6. Press [Button A] when finished to return to Timekeeping Mode.

If no buttons are pressed for a while, the watch will automatically return to Timekeeping Mode.

Alarm Mode

Setting a Daily Alarm

1. In Alarm Mode, press and hold [Button A] for 3 seconds. The hour digits will flash, indicating that it is selected for setting. The alarm is automatically turned ON at this point.
2. Press [Button B] to move between setting items: Hours → Minutes.
3. Press [Button C] to change the selected value.
4. Press [Button A] when finished.

Alarm Sound Check

In Alarm Mode, press [Button C] to sound the alarm.

Turning Alarm and Hourly Chime ON/OFF

In Alarm Mode, press [Button C] to cycle through the following settings: All ON → All OFF → Daily Alarm Only → Hourly Chime Only.

Hourly Chime

If the hourly chime is enabled, a short beep will sound at the start of each hour. You can stop the chime by pressing any button.

Stopwatch Mode

The Stopwatch Mode allows you to measure elapsed time, split times, and two-finish times. The maximum measuring time is 23 hours, 59 minutes, 59.99 seconds.

Measuring Elapsed Time

[Button C] (Start) → [Button C] (Stop) → [Button C] (Restart) → [Button C] (Stop) → [Button A] (Reset).

Measuring Split Times

[Button C] (Start) → [Button A] (Split Time. 'SPL' indicator appears) → [Button A] (Restart Split) → [Button C] (Stop) → [Button A] (Reset).

Dual Finish

[Button C] (Start) → [Button A] (Split. Displays first finisher's time) → [Button C] (Stop. Displays second finisher's time) → [Button A] (Cancel Split. Displays second finisher's time) → [Button A] (Reset).

Dual Time Mode

This mode allows you to view the local time in another city worldwide.

Setting Dual Time

1. In Dual Time Mode, press and hold [Button A] for 3 seconds. The hour digits will flash, indicating that it is selected for setting.
2. Press [Button B] to move between setting items: Hours → Minutes.
3. Press [Button C] to increase the selected value.
4. Press [Button A] when finished.

Illumination

Press [Button L] in any mode to turn on the illumination. The illumination uses LED panels, whose brightness decreases after a certain period of use. A faint audible signal may be emitted when the display is illuminated. This is due to the vibration of illumination elements and does not indicate a malfunction. The illumination may be difficult to see in direct sunlight. Frequent use of the illumination shortens battery life.

Adjusting Illumination Duration

In Timekeeping Mode, press and hold [Button C] for several seconds to cycle through illumination durations: 1 second → 3 seconds (indicator '3').

Technical Specifications

Accuracy

±15 seconds per month

Timekeeping Mode

Hours, minutes, seconds, year, month, day.

Calendar System

Auto calendar from 2000 to 2099.

Other

Time Display Format

12/24 hour format.

Dual Time Mode

Displays current time in a different time zone.

Alarm Sound

Daily alarm, hourly chime.

Stopwatch Mode

Maximum Measurement Range

23 hours, 59 minutes, 59.99 seconds.

Measurement Modes

Elapsed time, split time with reset, dual finish.

Other

Illumination (LED), adjustable illumination duration.

Product Information

Item Name

Wristwatch (Electronic / Electro-mechanical Quartz)

Brand

CASIO

Manufacturer

CASIO COMPUTER Co., Ltd.

Manufacturer Address

(CASIO COMPUTER Co., Ltd.)
6-2, Hon-machi 1-chome, Shibuya-ku, Tokyo 151-8543, Japan

Importer

OOO "Kasio", 127055, Moscow, Sushchevskaya St., Bldg. 27, Str. 1, Russia

Country of Origin

Japan

Warranty Period

1 year

Authorized Service Center Address for Claims

As specified in the warranty card.

Compliance

Product complies with GOST 26270-98 (clause 4.35)

Certificate of Conformity No. ROCC JP. АЯ46.Д42228 / ROCC JP. АЯ46.Д42071 / ROCC JP. АЯ46.Д42230