CASIO GW-M850 Module 3155

❗ IMPORTANT INFORMATION

Some water-resistant watches feature leather straps. Do not wear these watches while swimming or engaging in any other activity where the strap may be submerged in water.

Battery

When the first signs of low power appear (dim display or no backlight), replace the battery at your nearest CASIO dealer or distributor. The battery in your watch is a test battery installed by the manufacturer, so its service life may be shorter than that of a standard battery.

Water Resistance

Watches are classified by water resistance levels (from I to V). Refer to the table below to determine the appropriate usage for your watch.

Notes:

• I: Watches are not water-resistant. Avoid all contact with moisture.
• III: If exposed to salt water, rinse thoroughly with fresh water and dry.
• IV: If exposed to salt water, rinse thoroughly with fresh water and dry.
• V: Watches can be used for scuba diving (except for depths requiring helium-mixed gas).

⚠️ CAUTION!!!

For all types of watches, do not:

• Press buttons underwater
• Adjust hands underwater
• Unscrew the crown underwater

Caring for Your Watch

• Replace the rubber gasket that protects the watch from water and dust every 2-3 years.
• If moisture 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 band too tightly. A finger should fit between your wrist and the band.
• To clean the watch and band, use a dry, soft cloth or a soft cloth dampened with a mild solution of water and mild neutral detergent. Never use volatile agents (such as gasoline, thinners, spray cleaners, etc.).
• Store the watch in a dry place when not in use.
• Avoid contact with gasoline, cleaning solvents, aerosol sprays, adhesives, paints, etc. Chemical reactions with these materials can damage gaskets, the case, and the finish.
• Some watch bands feature silk-screened designs. Be careful not to damage these designs when cleaning the band.

For watches with resin bands...

• You may notice a white powdery substance on the band. This substance is harmless to your skin or clothing and can be easily wiped off with a soft cloth.
• Sweat or moisture on a resin band, or storage in a humid environment, can lead to damage, cracking, or tearing of the band. To ensure the longest possible life for your resin band, wipe it clean of dirt and moisture with a soft cloth as often as possible.

For watches with fluorescent cases and bands...

• Prolonged exposure to direct sunlight can cause the fluorescent color to gradually fade. If moisture gets on the watch, wipe it off as soon as possible.
• Prolonged contact with a wet surface can cause the fluorescent color to fade. Keep the fluorescent surface dry and avoid contact with other surfaces.
• Rubbing the fluorescent surface against another surface can transfer the fluorescent color to that surface.

CASIO COMPUTER CO., LTD. is not responsible for any damage that may result from the use of this watch, nor does it accept claims from third parties.

GENERAL DESCRIPTION OF MODES

The illustration shows the watch in the Timekeeping Mode.

Illustration shows a Casio watch with various buttons labeled A, B, C, D, and L. The display shows the time, date, and mode indicators.

Pressing the C button repeatedly cycles through the modes in the following order: Timekeeping Mode – Stopwatch Mode – Data Bank Mode – World Time Mode – Alarm Mode – Timer Mode – Timekeeping Mode.

Press the L button in any mode to turn on the backlight.

Calibration

This watch automatically adjusts its time based on calibration signals. You can also set the time manually.

Set your home city code:

1. In the Timekeeping Mode, press and hold the A button until the city code flashes, indicating the setting mode.
2. Use the D and B buttons to select your home city code.
3. Press the A button to exit the setting mode.

Calibration Signal

This watch receives calibration signals to update its time.

Signal transmitters are located in Germany (25 km from Frankfurt, 77.5kHz) and Anthorn, England (60kHz). The signal range is approximately 1,500 km. Signals may be weak at distances over 500 km.

In Japan, signal transmitters are located in Fukuoka/Saga (60kHz) and Fukushima (40kHz). The signal range is approximately 1,500 km. Signals may be weak at distances over 500 km.

In the USA, signal transmitters are located in Fort Collins, Colorado (60kHz). The signal range is approximately 3,000 km. Signals may be weak at distances over 1,000 km.

In China, a signal transmitter is located in Shangqiu. The signal range is approximately 1,500 km. Signals may be weak at distances over 500 km.

The broadcast signal is also affected by weather conditions, atmospheric pressure, and temperature. The signal may be weakened by the following factors:

• Being near a TV, computer, or other household appliances.
• Being in a subway or tunnel.
• Being near an airport, train station, or highway.
• Being near radio or signal transmission stations.
• Electrostatic noise.

There are two types of calibration signal reception.

With Auto Receive ON, the watch automatically receives the signal six times each day and corrects the time.

With Manual Receive ON, you press the button to receive the signal:

1. Place the watch horizontally.
2. In the signal reception mode, press and hold the D button until [RC] appears on the display.
3. Signal reception typically takes from 2 to 7 minutes, but can take up to 14 minutes. Do not move the watch during reception.
4. After reception is complete, the watch will display [GET] to indicate that the time has been adjusted.
5. Press the D button twice to return to the signal reception mode.

To stop the reception process and return to the signal reception mode, press the D button.

Auto Calibration Signal

• With Auto Receive ON, the watch automatically receives the signal six times (during the night or early morning).
• Auto Receive only occurs when the watch is in the Timekeeping or World Time Mode.
• Signal reception takes from 2 to 14 minutes. Do not move the watch during reception.

Turning Auto Calibration Signal ON/OFF

1. In the Timekeeping Mode, press the D button to view the last reception data.
2. Press and hold the A button until the [ON] or [OFF] indicator flashes, indicating the setting mode.
3. Note that Auto Receive settings cannot be made if your home city code does not support signal reception.
4. Press the D button to turn Auto Receive [ON] or [OFF].
5. Press the A button to exit the setting mode.

Viewing Last Reception Data

In the Timekeeping Mode, press the D button to view the last reception data.

Signal Reception Indicator

This indicator shows the signal reception strength: L1 (weak), L2, L3 (strong).

• Try to position the watch where it can receive a strong signal, free from interference.
• It takes about 10 seconds for the watch to establish a signal reception frequency, which is shown on the indicator.

STOPWATCH MODE

In this mode, you can use the stopwatch and the countdown timer simultaneously.

The stopwatch measurement range is up to 99 hours, 59 minutes, 59.99 seconds. When the measurement limit is reached, counting restarts from zero.

This watch allows you to select one of 10 preset countdown timers. You can also change the preset time for any timer. Use the B button to cycle through the timers:

Changing Countdown Timer Times

1. In the Stopwatch Mode, with the countdown timer set to zero, press and hold the A button until the time setting flashes.
2. Press the C button to cycle through the settings. The hour digits will flash.
3. Use the D and B buttons to select the time value you want to change.
4. Use the D and B buttons to change the hour value.
5. Press the C button to move to the minute setting.
6. Use the D and B buttons to change the minute value.
7. Press the A button to exit the setting mode.

Auto-Start Function

• Press the D button to start the auto-start countdown (a countdown before the measurement begins). The measurement will start automatically when the countdown reaches zero.
• The backlight and a beep sound will activate at 50, 40, 30, 20, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, and 0 seconds.
• You can stop the countdown at any point and switch to measurement by pressing the D button.
• You can stop the countdown and return to the starting countdown time by pressing the B button.

Stopwatch Function

• Press the D button to pause measurement (while the stopwatch or timer is running).
• The measured time will be frozen on the display for 1 to 2 minutes, while measurement continues (stopwatch and countdown timer).
• You can save this value to the watch's data bank or reset the measurement to zero. If you do nothing, the watch will automatically return to the measurement display.
• Press the B button to save the measured/frozen stopwatch value. Measurement continues.
• You can save up to 30 records in the watch's memory. If the data bank is full, new records will overwrite the oldest ones.
• To reset the measurement to zero while a split time is displayed, press and hold the B button for a few seconds.
• Similarly, you can stop the measurement by pressing and holding the B button for a few seconds.
• To check the remaining time for a countdown, press the B button during measurement. Note that if the countdown is set to [OFF], you cannot check this value.
• The backlight and a short beep will activate at 5, 3, 1 minute, and 30, 10, 5, 4, 3, 2, 1 seconds remaining for the countdown timer.

DATA BANK MODE

In this mode, you can view saved stopwatch data.

You can also view the total stopwatch measurement time from the Stopwatch Mode.

• Use the D and B buttons to move between records.
• Press both the D and B buttons simultaneously to go to the total elapsed time record.

Pressing the A button while viewing a record allows you to see the date and time that record was made.

The total elapsed time record is limited to 2999 hours, 59 minutes, and 57 seconds. When the total elapsed time exceeds 100 hours, the hour and minute digits will change at 2-second intervals.

Adjusting Saved Time Records

You can measure saved time values. The total elapsed time will change accordingly.

1. Press and hold the A button until the time setting flashes.
2. Use the D and B buttons to adjust the 1/10 second value.
3. Press the C button to move to the second setting. The second digits will flash.
4. Use the D and B buttons to adjust the second value.
5. Press the C button to move to the minute setting.
6. Use the D and B buttons to adjust the minute value.
7. Press the C button to move to the hour setting.
8. Use the D and B buttons to adjust the hour value.
9. Press the A button to exit the setting mode.

Deleting Saved Data

1. Press the D and B buttons to display the total elapsed time.
2. Press and hold the A button until the time setting flashes.
3. Press both the D and B buttons to delete the saved records.
4. Press the A button to exit the setting mode.

WORLD TIME MODE

In this mode, you can view the local time in any of 48 cities (29 time zones).

World Time values are automatically set to the current time.

Viewing Current Time in Another City

In World Time Mode, press the D and B buttons to select the city whose time you want to view.

Daylight Saving Time (DST) Setting

1. Use the D and B buttons to select the city for which you want to change the DST setting.
2. Press the A button to turn DST [ON] or [OFF].

ALARM MODE

You can set up to five different alarms. An alarm will sound for 10 seconds at the set time.

• If the Hourly Chime is [ON], a short beep will sound at the top of every hour.
• If the Snooze Alarm is [ON], the alarm will sound again up to seven times at five-minute intervals until you turn it off.

Setting an Alarm

1. In the Alarm Mode, press the D button to select an alarm type: [AL1], [AL2], [AL3], [AL4], [SNZ] (Snooze Alarm), or [SIG] (Hourly Chime).
2. Press and hold the A button. The hour digits will flash, indicating the setting mode. The alarm is automatically turned [ON] when you set the time.
3. Press the C button to cycle through the settings: Hour – Minute – Month – Day – Hour.
4. Use the D button to increase and the B button to decrease the selected value.

The type of alarm depends on the values you enter:

• Daily Alarm (sounds every day at the specified time): When setting, enter "-" for the month and day.
• Date Alarm (sounds at the specified time on the specified date).
• Monthly Alarm (sounds every month on the specified day and time): When setting, enter "-" for the day.

The time format (12-hour or 24-hour) matches the format you selected for timekeeping.

When using the 12-hour format, be careful to set the time correctly as [AM] or [PM].

Press the A button to return to the Timekeeping Mode.

Testing an Alarm

In the Alarm Mode, press the D button to test the alarm sound.

Turning Alarms/Hourly Chime ON/OFF

1. In the Alarm Mode, press the D button to select an alarm type.
2. Press the B button to turn it [ON] or [OFF].

• When a regular alarm is selected, [ALM] appears on the display.
• When the Hourly Chime is selected, [SIG] appears on the display.
• When the Snooze Alarm is selected, [SNZ] appears on the display.

STOPWATCH MODE

The Stopwatch Mode allows you to record lap times, split times, and finish times for two finishers.

The total elapsed time measurement range is 23 hours, 59 minutes, 59.99 seconds.

Measuring Lap Times

D (Start) – D (Stop) – D (Lap/Split) – D (Stop) – B (Reset).

Measuring Split Times

D (Start) – B (Split Time. [SPL] Indicator) – B (Restart Split) – D (Stop) – B (Reset).

Two Finishers

D (Start) – B (Split. First finisher's time displayed) – D (Stop. Second finisher's time displayed) – B (Cancel Split. Second finisher's time displayed) – D (Reset).

COUNTDOWN TIMER MODE

The countdown timer can be set from one minute up to 24 hours.

When the countdown reaches zero, a long beep sounds.

Setting the Timer

1. In the Timer Mode, press and hold the A button while the start time is displayed. The hour digits will flash, indicating the setting mode.
2. Press the C button to cycle through the settings: Hour – Minute – Hour.
3. Use the D button to increase and the B button to decrease the selected value.
4. To set the countdown timer to 24 hours, enter "0:00".
5. Press the A button to exit the setting mode.

Using the Timer

1. Press the D button in the Timer Mode to start the countdown.
2. Press the D button again to stop the countdown.
3. You can resume the countdown by pressing the D button. After stopping the countdown, you can press the B button to reset the countdown time to the starting value.

TIMEKEEPING MODE

In the Timekeeping Mode, pressing the B button allows you to view the current time in the city you last selected in the World Time Mode.

In the Timekeeping Mode, press and hold the A button until the city code flashes, indicating the setting mode.

Press the C button to cycle through the settings: City Code – [DST] – 12/24 Hour Format – Seconds – Hour – Minute – Year – Month – Day – Battery Power Saving Mode – City Code.

If you select seconds for adjustment (the seconds digits flash), press the D button to reset the seconds to 00. If you press the D button when the seconds are between 30 and 59, the seconds will reset to 00 and the minutes will advance by one. If the seconds are between 00 and 29, the minutes will not change.

Use the D button to increase and the B button to decrease the selected value.

The day of the week is set automatically according to the date.

The date can be set from January 1, 2001, to December 31, 2099.

• Use the D and B buttons to select a city code.
• Press the D button to select auto [DST] ([AUTO]), [DST] [ON], or [DST] [OFF].
• Press the D button to switch between 12-hour and 24-hour formats.

In the 12-hour format, "P" indicates [PM].

Press the D button to turn the Battery Power Saving Mode [ON] or [OFF].

Press the A button to return to the Timekeeping Mode.

Backlight

• Press the L button in any mode to turn on the watch's backlight.
• Use the B button to select the backlight duration: 1.5 seconds or 3 seconds.
• The backlight uses electro-luminescent (EL) panels, whose brightness decreases after a certain period of use.
• The watch emits an audible sound when the backlight is on. This is due to the vibration of the EL panel and does not indicate a malfunction.
• The backlight is difficult to see in direct sunlight.
• Frequent use of the backlight reduces battery life.

Auto Light

• The Auto Light feature turns on the backlight automatically whenever your arm is angled at 40° or more towards the ground.
• Do not use the Auto Light feature in situations where the light could cause injury or distraction, such as when riding a motorcycle or bicycle.
• To turn on the Auto Light feature in the Timekeeping Mode, press and hold the L button for three seconds.
• When Auto Light is [ON], the display will show the [A.EL] indicator.

Turning Button Tone ON/OFF

In any mode, press and hold the C button for several seconds to turn the button tone [ON] ([MUTE]) or [OFF].

POWER SOURCE

This watch is powered by a solar rechargeable battery. It also has a backup battery that is charged by the solar battery.

If your watch is kept in the dark for extended periods, the rechargeable battery's charge will deplete.

Battery Power Indicator

The battery power indicator is located at the bottom of the display.

If there is no indicator on the display, the battery is fully discharged. Place the watch in a well-lit area.

Be careful not to leave your watch in direct sunlight for extended periods, as this may cause malfunctions.

If you use the backlight or alarm frequently, the [LMH] indicator will appear on the display, indicating that the battery needs charging.

Charging the Battery

After a full charge, the watch will operate for approximately 7 months under the following conditions:

• Watch is not exposed to sunlight.
• Backlight used 1.5 seconds/day.
• Alarm used 10 seconds/day.
• Stopwatch used 26 times/day.
• Watch operated for 18 hours/day, with 6 hours/day in sleep mode.
• Calibration signal reception 4 minutes/day.

By exposing the watch to sunlight every day, you can ensure continuous battery charging:

The following table shows the time required to charge the battery:

POWER SAVING MODE

The sleep mode saves battery power when the watch is kept in the dark.

The following table shows the availability of watch functions while in sleep mode:

Turning Power Saving Mode ON/OFF

1. In the Timekeeping Mode, press and hold the A button until the city code flashes, indicating the setting mode.
2. Press the C button nine times to advance to the Power Saving Mode setting.
3. Press the D button to turn the power saving mode [ON] or [OFF].
4. Press the A button to exit the setting mode.

When the mode is [ON], "[PS]" will appear on the display. Your watch may also enter sleep mode automatically. To return the watch to normal operation, place it in a well-lit area or press any button.

SPECIFICATIONS

Product Information