Casio Module 1646 User Manual
This manual provides instructions for operating and caring for your Casio Module 1646 watch.
Care for Your Watch
Battery
If the watch shows signs of low power (e.g., dim display, no backlight), replace the battery at an authorized CASIO dealer. The battery included with your watch is for initial testing purposes and may have a shorter lifespan than a standard battery.
Water Resistance
Your watch is classified by its water resistance level, indicated by Roman numerals from I to V. Consult the table below to understand the appropriate usage for your watch's rating.
| Rating | Splash, Rain, etc. | Swimming, Washing Car, etc. | Swimming, Snorkeling, etc. | SCUBA Diving, etc. |
| I | Yes | No | No | No |
| II | Yes | Yes | No | No |
| III | Yes | Yes | No | No |
| IV | Yes | Yes | Yes | No |
| V | Yes | Yes | Yes | Yes |
| 300 M WATER RESISTANT | Yes | Yes | Yes | Yes |
Notes:
- Water resistance is not permanent. Avoid exposure to any moisture.
- Do not press buttons underwater.
- If your watch is exposed to saltwater, rinse it thoroughly with fresh water and dry it completely.
- Watches rated for 200M or 300M water resistance can be used for SCUBA diving, but not for diving that requires helium-oxygen gas mixtures.
- Some water-resistant watches have leather straps. Do not wear these models while swimming or engaging in any activity where the strap may become wet.
Watch Care
- Never attempt to open the case or remove the back cover yourself.
- The gasket that provides water and dust resistance should be replaced every 2 to 3 years by an authorized dealer.
- If moisture enters the watch, have it inspected immediately by an authorized CASIO dealer.
- Avoid exposing the watch to extremely low or high temperatures.
- While designed for normal use, avoid rough handling and dropping the watch.
- Do not overtighten the strap. 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 a mild neutral detergent solution. Never use volatile substances like alcohol, solvents, spray cleaners, etc.
- Avoid contact with hairspray, cologne, sunscreen, and other toiletries, as these can damage the watch's plastic parts. If contact occurs, wipe the watch immediately with a dry, soft cloth.
- Store the watch in a dry place when not in use.
- Avoid contact with gasoline, cleaning solvents, aerosol sprays, adhesives, paint, etc. Chemical reactions can damage gaskets, the case, and the watch's finish.
- Some models have silk-screened designs on the strap. Clean these straps gently to avoid damaging the prints.
- In very cold conditions, buttons may freeze and become unresponsive. They will function normally once the watch is brought to a warmer temperature.
Product Information
Name: Electronic/Electro-mechanical Quartz Wristwatch (Men's/Women's)
Brand: CASIO
Manufacturer: CASIO COMPUTER Co., Ltd.
Manufacturer Address: 6-2, Hon-machi 1-chome, Shibuya-ku, Tokyo 151-8543, Japan
Importer: ООО «Касио», 127055, Москва, ул. Сущевская, д.27, стр. 1, Россия
Country of Origin: Japan
Warranty Period: 1 year
Authorized Service Address: Refer to the warranty card.
Conformity: Meets GOST 26270-98 (cl. 4.35). Certificate of Conformity No. ROCC JP. АЯ46.Д00003
How to Adjust Strap Length
To adjust the length of a leather strap:
- To release the strap, pull the tab on the inside of the buckle, then slide the strap in or out to adjust the length. Caution: The tab's resistance is strong; do not use your fingernail. Use a screwdriver or similar tool.
- Once the desired length is set, fold the tab back down to secure it.
How to Trim Strap End
After adjusting the strap length, you may trim the excess strap end that protrudes from the buckle. If you choose to do this, it is recommended to trim about 5-10 mm from the buckle tip.
Caution:
- Handle scissors and other cutting tools with care to avoid injury.
- Be careful not to cut too much. It may be better to trim a little at a time until you achieve the desired length.
- If the threads of the remaining strap end become loose after trimming, do not pull them. Trim any loose threads with scissors.
General Guide
- Press the 'C' button to switch between modes. Pressing 'C' in any mode after an operation returns you to the timekeeping mode.
- You can activate the backlight for approximately 2 seconds in any mode (except during setting operations) by pressing the 'B' button.
Mode Diagram: Current Time Mode, Thermometer Mode, Sunrise/Sunset Mode, Alarm Mode, Countdown Timer Mode, Sound Signal Mode.
Current Time Mode
How to Set Current Time and Date
- In the timekeeping mode, press and hold the 'A' button until the seconds digits on the display start to flash. This indicates that the seconds can be changed.
- Press the 'C' button to cycle through the setting fields in the following order: Seconds, Minutes, Hours, Year, Month, Day, 12/24 Hour Format.
- While the seconds digits are flashing, press the 'D' button to reset them to '00'. If the seconds are between 30 and 59 when you press 'D', the minutes will be incremented by one. If the seconds are between 00 and 29, the minutes will remain unchanged.
- While any other digits (except seconds) are flashing, press 'D' to increase the value or 'B' to decrease it. For the day of the week, 'D' advances to the next day, and 'B' goes to the previous day. For the 12/24 hour format, press 'D' to toggle between the two.
- When setting any value other than seconds or the 12/24 hour format, holding down either button allows for faster adjustment.
- If the 12-hour format is selected, the 'P' indicator appears for PM times, and 'A' for AM times. The '24' indicator appears for the 24-hour format.
- After setting the current time and date, press the 'A' button to return to the timekeeping mode.
Notes:
- The date can be set from January 1, 1995, to December 31, 2039.
- If you do not press any button for several minutes while digits are flashing, the display will stop flashing, and the watch will automatically return to the timekeeping mode.
Illumination
Auto Illuminator Function
If the Auto Illuminator function is enabled, the backlight will turn on for approximately 2 seconds whenever the watch is tilted towards you. Do not wear the watch on the inside of your wrist, as this may cause the Auto Illuminator to activate unintentionally, reducing battery life.
Tilt your wrist so that the watch is parallel to the ground, then tilt it towards you by about 40°. The backlight will activate.
Notes:
- The backlight may not activate if your hand is tilted more than 15° to the left or right of the parallel position. Ensure your hand is parallel to the ground.
- Static electricity or magnetic fields can interfere with the Auto Illuminator function. If it does not activate, return the watch to its original position (parallel to the ground) and tilt it towards you again. If this fails, lower your arm along your body, then raise it again and repeat the procedure.
- Under certain conditions, the backlight may activate with a slight delay of up to 1 second. This is normal and does not indicate a malfunction.
- The backlight uses an electroluminescent light source that may degrade over time with prolonged use. Frequent use of the backlight reduces battery life.
- A sound may be heard when the backlight is on. This is due to vibration of the electroluminescent panel and is normal.
How to Connect or Disconnect the Auto Illuminator Function
In the timekeeping mode, press and hold the 'D' button for one to two seconds to connect or disconnect the Auto Illuminator function. An indicator will appear on the display when the function is connected.
Note: To prevent premature battery drain, the Auto Illuminator function automatically disconnects approximately two hours after it is connected. Repeat the procedure to reconnect it.
Pressing the 'B' button at any time activates the backlight, regardless of the Auto Illuminator setting.
Warnings:
- Do not attempt to read the watch display in the dark while climbing or in other hazardous situations. This is dangerous and could lead to serious injury.
- Do not attempt to read the watch display while walking near roads or in areas with vehicle or pedestrian traffic. This is dangerous and could lead to injury or accidents.
- Do not attempt to read the watch display while riding a bicycle or driving a motorcycle or car. This is dangerous and could lead to injury or accidents.
- Before riding a bicycle, motorcycle, or car, ensure the Auto Illuminator function is turned OFF. Sudden activation of the Auto Illuminator could distract you, leading to an accident and serious injury.
Time Zone Tables
Asia and South Pacific
| No. | City | Time Difference from GMT | Longitude | Latitude |
| 1 | DHAKA | +6 | 90°E | 24°N |
| 2 | BANGKOK | +7 | 100°E | 14°N |
| 3 | JAKARTA | +7 | 107°E | 6°S |
| 4 | PHNOM PENH | +7 | 105°E | 12°N |
| 5 | HANOI | +7 | 106°E | 21°N |
| 6 | VIENTIANE | +7 | 103°E | 18°N |
| 7 | HONG KONG | +8 | 114°E | 22°N |
| 8 | SINGAPORE | +8 | 104°E | 1°N |
| 9 | KUALA LUMPUR | +8 | 102°E | 3°N |
| 10 | BEIJING | +8 | 116°E | 40°N |
| 11 | TAIPEI | +8 | 122°E | 25°N |
| 12 | MANILA | +8 | 121°E | 15°N |
| 13 | PERTH | +8 | 116°E | 32°S |
| 14 | ULAN BATOR | +8 | 107°E | 48°N |
| 15 | TOKYO | +9 | 140°E | 36°N |
| 16 | SEOUL | +9 | 127°E | 38°N |
| 17 | PYONGYANG | +9 | 126°E | 39°N |
| 18 | SYDNEY | +10 | 151°E | 34°S |
| 19 | MELBOURNE | +10 | 145°E | 38°S |
| 20 | GUAM | +10 | 145°E | 13°N |
| 21 | NOUMEA | +11 | 166°E | 22°S |
| 22 | PORT VILA | +11 | 168°E | 18°S |
| 23 | WELLINGTON | +12 | 175°E | 41°S |
| 24 | CHRISTCHURCH | +12 | 173°E | 43°S |
| 25 | SUVA | +12 | 178°E | 18°S |
| 26 | NAURU ISLAND | +12 | 166°E | 1°S |
| 27 | PAPEETE | -10 | 150°W | 18°S |
Note: Add one hour for Daylight Saving Time (e.g., if GMT is +2, DST is +3).
Designations: 'N' [North], 'S' [South], 'W' [West], 'E' [East].
Europe
| No. | City | Time Difference from GMT | Longitude | Latitude |
| 1 | AZORES ISLANDS | -1 | 25°W | 38°N |
| 2 | LONDON | +0 | 0°E | 51°N |
| 3 | DUBLIN | +0 | 6°W | 53°N |
| 4 | LISBON | +0 | 9°W | 39°N |
| 5 | CASABLANCA | +0 | 8°W | 34°N |
| 6 | PARIS | +1 | 2°E | 49°N |
| 7 | MILAN | +1 | 9°E | 45°N |
| 8 | ROME | +1 | 12°E | 42°N |
| 9 | MADRID | +1 | 4°W | 40°N |
| 10 | AMSTERDAM | +1 | 5°E | 52°N |
| 11 | HAMBURG | +1 | 10°E | 54°N |
| 12 | FRANKFURT | +1 | 9°E | 50°N |
| 13 | VIENNA | +1 | 16°E | 48°N |
| 14 | STOCKHOLM | +1 | 18°E | 59°N |
| 15 | ATHENS | +2 | 24°E | 38°N |
| 16 | HELSINKI | +2 | 25°E | 60°N |
| 17 | ISTANBUL | +2 | 29°E | 41°N |
Note: Add one hour for Daylight Saving Time (e.g., if GMT is +2, DST is +3).
Africa and Middle East
| No. | City | Time Difference from GMT | Longitude | Latitude |
| 1 | BEIRUT | +2 | 35°E | 34°N |
| 2 | DAMASCUS | +2 | 36°E | 33°N |
| 3 | CAPE TOWN | +2 | 18°E | 34°S |
| 4 | KUWAIT | +3 | 48°E | 29°N |
| 5 | RIYADH | +3 | 47°E | 25°N |
| 6 | JEDDAH | +3 | 39°E | 21°N |
| 7 | ADEN | +3 | 45°E | 13°N |
| 8 | ADDIS ABABA | +3 | 39°E | 9°N |
| 9 | NAIROBI | +3 | 37°E | 1°S |
| 10 | DUBAI | +4 | 55°E | 25°N |
| 11 | ABU DHABI | +4 | 54°E | 24°N |
| 12 | MUSCAT | +4 | 58°E | 23°N |
| 13 | KARACHI | +5 | 67°E | 25°N |
| 14 | PRAYA | -1 | 23°W | 15°N |
| 15 | DAKAR | +0 | 17°W | 15°N |
| 16 | ABIDJAN | +0 | 4°W | 5°N |
Note: Add one hour for Daylight Saving Time (e.g., if GMT is +2, DST is +3).
How to Use the Strap
How to Fasten Strap to Your Wrist
For watches with leather straps (like the one shown below), adjust the length using the following procedure.
- Thread the strap end through the slot in the buckle cover and the retaining loop.
- Place the buckle over the two metal tabs and press down until it clicks into place.
- Close the buckle cover, pressing down until it locks.
To remove the strap, pull the sides of the buckle cover with your thumb and index finger to release it, then unfasten the strap.
North America
| No. | City | Time Difference from GMT | Longitude | Latitude |
| 1 | PAGO PAGO | -11 | 171°W | 14°N |
| 2 | HONOLULU | -10 | 158°W | 21°N |
| 3 | ANCHORAGE | -9 | 150°W | 61°N |
| 4 | HOMER | -9 | 165°W | 65°N |
| 5 | LOS ANGELES | -8 | 118°W | 34°N |
| 6 | SAN FRANCISCO | -8 | 122°W | 38°N |
| 7 | LAS VEGAS | -8 | 115°W | 36°N |
| 8 | VANCOUVER | -8 | 123°W | 49°N |
| 9 | SEATTLE | -8 | 122°W | 48°N |
| 10 | DENVER | -7 | 105°W | 40°N |
| 11 | EL PASO | -7 | 106°W | 32°N |
| 12 | EDMONTON | -7 | 114°W | 54°N |
| 13 | CHICAGO | -6 | 88°W | 42°N |
| 14 | HOUSTON | -6 | 95°W | 30°N |
| 15 | DALLAS | -6 | 97°W | 33°N |
| 16 | NEW ORLEANS | -6 | 90°W | 30°N |
| 17 | WINNIPEG | -6 | 97°W | 50°N |
| 18 | MEXICO CITY | -6 | 99°W | 19°N |
| 19 | NEW YORK | -5 | 74°W | 41°N |
| 20 | MONTREAL | -5 | 74°W | 45°N |
| 21 | DETROIT | -5 | 83°W | 42°N |
| 22 | MIAMI | -5 | 80°W | 26°N |
| 23 | BOSTON | -5 | 71°W | 42°N |
Note: Add one hour for Daylight Saving Time (e.g., if GMT is +2, DST is +3).
Designations: 'N' [North], 'S' [South], 'W' [West], 'E' [East].
Thermometer Mode
The watch's built-in sensor measures ambient temperature, which is displayed on the watch face. The thermometer can be calibrated to correct for errors.
Caution:
- Temperature readings are affected by body heat (when worn on the wrist), direct sunlight, and moisture. For the most accurate temperature readings, remove the watch from your wrist and place it in a well-ventilated area away from direct sunlight. Wipe the watch case dry. The watch case temperature will stabilize to the ambient temperature in about 20-30 minutes.
- Accurate temperature measurements cannot be taken while the watch is worn on the wrist. The graph below illustrates the influence of body temperature on ambient temperature readings.
[Diagram showing temperature graph with body heat influence]
Temperature Measurement
- The temperature graph on your watch updates automatically every five minutes, regardless of the mode (unless you are performing a setting operation). These readings can only be viewed in the thermometer mode.
- In the thermometer mode, press the 'D' button to take a temperature measurement. The measured temperature will appear on the display.
[Diagram showing temperature graph display with current reading]
Note: If the measured temperature is outside the range of -20°C to 60°C, the display will show "--.-°C". Normal readings will resume once the temperature returns to within the acceptable range.
Temperature Sensor Calibration
The watch's built-in temperature sensor is factory calibrated before shipment, and further adjustment is usually not required. However, if you notice significant errors in temperature measurements, you can calibrate the watch yourself.
Caution: Incorrect calibration of the temperature sensor can lead to inaccurate readings. Read the following instructions carefully before proceeding.
To calibrate the temperature sensor:
- In the thermometer mode, press and hold the 'A' button until the temperature digits on the display start to flash. This indicates that the temperature value can be changed.
- Pressing the 'D' button increases the temperature reading by 0.1°C, and pressing 'B' decreases it by 0.1°C.
- You can calibrate the temperature sensor within a range of -9.9°C to +9.9°C.
- To reset the calibration to the factory setting, press the 'B' and 'D' buttons simultaneously.
- After completing the calibration, press the 'A' button to return to the thermometer mode.
If you do not press any button for several minutes while digits are flashing, the display will stop flashing, and the watch will automatically return to the thermometer mode.
Central and South America
| No. | City | Time Difference from GMT | Longitude | Latitude |
| 1 | PANAMA | -5 | 80°W | 9°N |
| 2 | LIMA | -5 | 77°W | 12°S |
| 3 | BOGOTA | -5 | 74°W | 5°N |
| 4 | CARACAS | -4 | 67°W | 10°N |
| 5 | LA PAZ | -4 | 68°W | 17°S |
| 6 | SANTIAGO | -4 | 71°W | 33°S |
| 7 | PORT OF SPAIN | -4 | 61°W | 11°N |
| 8 | RIO DE JANEIRO | -3 | 43°W | 23°S |
| 9 | SAO PAULO | -3 | 47°W | 24°S |
| 10 | BRASILIA | -3 | 48°W | 16°S |
| 11 | BUENOS AIRES | -3 | 58°W | 35°S |
| 12 | MONTEVIDEO | -3 | 56°W | 35°S |
Note: Add one hour for Daylight Saving Time (e.g., if GMT is +2, DST is +3).
Designations: 'N' [North], 'S' [South], 'W' [West], 'E' [East].
How to Display Sunrise and Sunset Times for a Specific Date
- Use the 'C' button to enter the Sunrise/Sunset mode. When entering this mode from another mode, the display will show sunrise and sunset times for the current day (as set in the timekeeping mode).
- Press the 'D' button to advance to the next date. Holding down 'D' will return to the current date.
- After displaying the desired date, wait approximately 15 seconds for the watch to perform internal calculations. The sunrise and sunset times for that date will then appear on the display.
Notes:
- If you suspect incorrect information, verify your settings: Year, Time Difference from GMT, Longitude, Latitude, East/West, North/South.
- Sunrise and sunset times are calculated for sea level. Actual times may vary slightly depending on your altitude.
- Sunrise and sunset times are accurate to within 5 minutes for latitudes below 50 degrees, and within 10 minutes for latitudes above 50 degrees.
Technical Specifications
- Timekeeping Accuracy: ±15 seconds per month (at normal temperatures).
- Timekeeping: Hour, minute, second, AM/PM indicator, year, month, day, day of week, temperature graph.
- Time Format: 12-hour and 24-hour format switching.
- Calendar System: Auto calendar, programmed from 1995 to 2039.
- Graphic Display: Temperature graph (displayed in all modes).
- Thermometer Functions:
- Measurement Range: -20°C to 60°C.
- Display Range: 20.0°C to 60.0°C.
- Unit of Measure: 0.1°C.
- Measurement Interval: Every 5 minutes.
- Other Features: Temperature sensor calibration function.
- Temperature Sensor Accuracy: ±2°C within 10°C to 40°C; ±3°C within -20°C to 60°C.
- Countdown Timer Functions:
- Unit of Measure: 1 second.
- Setting Range: 1 minute to 60 minutes.
- Alarm: Daily alarm, hourly chime.
- Sunrise/Sunset Mode: Sunrise/sunset times for a specified date.
- Illumination: Electro-luminescent backlight, auto and manual.
- Other Functions: Low temperature resistance (-20°C).
- Power: One lithium battery (Type CR2016).
- Battery Life: Approximately 2 years under the following conditions: 5 seconds of alarm use per day, 20 seconds of illumination use per day.
Alarm Mode
Daily Alarm and Hourly Chime
If the daily alarm is set, it will sound for 20 seconds at the preset time each day. Press any button to stop the alarm. If the hourly chime is set, the watch will chime at the top of every hour.
How to Set the Daily Alarm Time
- In the alarm mode, press the 'A' button. The hour digits will flash, indicating that the alarm time can be set. The daily alarm setting is automatically turned ON.
- Press the 'C' button to cycle through the setting fields: Hours, Minutes.
- Press 'D' to increase the flashing digits or 'B' to decrease them. Holding down either button allows for faster adjustment.
- The time format (12-hour or 24-hour) matches the format set in the timekeeping mode.
- If using the 12-hour format, be careful to set the correct AM ('A' indicator) or PM ('P' indicator) time.
- After setting the alarm time, press the 'A' button to return to the alarm mode.
If you do not press any button for several minutes while digits are flashing, the display will stop flashing, and the watch will automatically return to the alarm mode.
How to Enable or Disable Daily Alarm and Hourly Chime Settings
In the alarm mode, press the 'D' button to cycle through the settings for the daily alarm and hourly chime.
[Diagram showing indicators for Daily Alarm ON/OFF and Hourly Chime ON/OFF]
How to Test Alarm Sound
To test the alarm sound, press and hold the 'D' button in the alarm mode.
Sunrise/Sunset Mode
How to Set Geographic Coordinates
Before using the sunrise/sunset function, ensure the current time and geographic coordinates for your location are set correctly. This function allows you to determine sunrise and sunset times for a specific date.
- In the sunrise/sunset mode, press and hold the 'A' button. The digits for the time difference from GMT will start to flash, indicating they can be changed.
- Press the 'C' button to cycle through the setting fields: Time Difference from GMT, Longitude/Latitude.
- While the time difference digits are flashing, press 'D' to increase the value. Holding 'D' allows for faster adjustment.
- While the longitude/latitude digits are flashing, press 'D' to adjust longitude or 'B' to adjust latitude. Holding either button allows for faster adjustment.
[Diagram showing longitude and latitude adjustment]
Designations: 'N' [North], 'S' [South], 'W' [West], 'E' [East].
- After setting the geographic coordinates, press the 'A' button to return to the sunrise/sunset mode.
Notes:
- If you do not press any button for several minutes while digits are flashing, the display will stop flashing, and the watch will automatically return to the sunrise/sunset mode.
- Latitude can be set from 65° North to 65° South.
- For longitude, always set '0°E' for 0° and '180°E' for 180°.
- When observing Daylight Saving Time, remember to add one hour to the time difference from GMT.
Warning: After completing setting changes, the watch requires time to process the new data, indicated by moving graphics on the display. Wait for the graphics to stop before performing new operations.
Countdown Timer Mode
How to Set the Countdown Time
- In the countdown timer mode, press and hold the 'A' button. The minute digits will flash, indicating they can be changed.
- Press 'D' to increase the flashing digits or 'B' to decrease them. Holding either button allows for faster adjustment.
- After setting the time, press the 'A' button to return to the countdown timer mode.
If you do not press any button for several minutes while digits are flashing, the display will stop flashing, and the watch will automatically return to the countdown timer mode.
How to Use the Countdown Timer
- In the countdown timer mode, press the 'D' button to start the countdown timer.
- Press the 'D' button again to stop the countdown timer.
- You can resume the countdown timer by pressing 'D' again.
- Stop the timer, then press 'A' to reset the countdown time to its original setting.
