Watch Catalog

Casio module 3509

Quartz module. 3509 is the number engraved on the caseback of these watches, and Casio files its operation manual under it. 1 watch in the catalog runs on it.

How to operate module 3509

Short steps in our words. The buttons are lettered as in Casio's operation guide, where each task's page is given.

Set the time and date

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press C to move through the settings: Home City, summer time, seconds, hours, minutes, year, month, day, then 12/24-hour and the other settings.
  3. On the seconds, press D to reset them to 00.
  4. On any other setting, use B and D to change it (hold for fast).
  5. To switch between 12-hour and 24-hour format, press C eight times from the Home City name until 12H or 24H flashes, then press D to toggle.
  6. Press A to go back to the Timekeeping Mode.

Good to know

Paired with a phone running CASIO WATCHES, the watch corrects its time four times a day, at around 12:30 a.m., 6:30 a.m., 12:30 p.m. and 6:30 p.m.; setting it by hand is for when it cannot connect with a phone.

To take the time from a paired phone now: with the phone within one meter, press D in the Timekeeping Mode. TIME flashes, then OK shows and the time is adjusted.

Resetting the seconds between 30 and 59 adds 1 to the minutes.

The watch leaves the setting screen by itself after about two or three minutes without a button press.

To turn auto time adjustment off, for example on an aircraft: hold A until the Home City name shows, press C 13 times until RCVD shows, press D to choose OFF or On, then press A. This can be changed only while the watch is paired with a phone.

From Casio's guide, page 14

Summer time

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press C.
  3. Press D to cycle through AUTO (switches by itself), OFF (always standard time) and ON (always summer time).
  4. Press A to go back to the Timekeeping Mode.

Good to know

The factory default for all cities is AUTO.

Setting the time by hand on the watch cancels the automatic switching between standard time and summer time.

A World Time city has its own summer time setting: in the World Time Mode, show the city, hold A for about two seconds, press D to choose AUTO, OFF or ON, then press A. It cannot be set while UTC is shown.

From Casio's guide, page 14

Home City

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Use B and D to change the Home City (hold for fast).
  3. Press A to go back to the Timekeeping Mode, or press C first to set its summer time.

Good to know

In the World Time Mode, press A and B together to swap the Home City time with the World Time.

Auto time adjustment does not work for 24 hours after the Home Time and World Time are swapped with the CASIO WATCHES app.

From Casio's guide, page 14

Set an alarm

  1. Press C until the Alarm Mode (AL) shows, after the World Time, Stopwatch and Timer Modes.
  2. Press D until the alarm you want, AL1 to AL5, shows.
  3. Hold A for at least two seconds and release it when the hour digits flash.
  4. Use B and D to set the hour (hold for fast); in 12-hour format, P marks p.m.
  5. Press C: the minute digits flash. Use B and D to set the minutes.
  6. Press A to exit the setting screen, then hold C for at least one second to go back to the Timekeeping Mode.
  7. To switch an alarm on or off, show it with D in the Alarm Mode and press A.
  8. For the hourly time signal, press D until SIG shows and press A to switch it on or off.

Good to know

An alarm sounds for 10 seconds; press any button to stop it.

ALM shows while any alarm is on, and SIG while the hourly time signal is on.

An alarm does not sound when the battery is low.

You can also set alarms with the CASIO WATCHES app.

From Casio's guide, page 17

Light

  1. Press B to light the face.
  2. To switch Auto Light on or off, hold B for at least three seconds in the Timekeeping Mode; LT shows while it is on, and the face then lights whenever the watch is angled 40 degrees or more.
  3. To choose how long the light stays on: hold A until the Home City name shows, press C 12 times until LIGHT shows, press D to choose 1 (1.5 seconds) or 3 (3 seconds), then press A.

Good to know

Auto Light switches itself off after about six hours.

The light does not work while an alarm, the timer or another beeper sounds.

Frequent use of the light runs down the battery.

From Casio's guide, page 7

Button tone

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press C 11 times until KEY♪ or MUTE flashes.
  3. Press D to choose KEY♪ (tone on) or MUTE (tone off).
  4. Press A to go back to the Timekeeping Mode.

Good to know

Alarm and timer tones still sound while the button tone is muted.

From Casio's guide, page 21

Stopwatch

  1. Press C until the Stopwatch Mode (ST) shows, after the World Time Mode.
  2. Press D to start, D to stop, and D again to resume.
  3. For a split time, press A while it runs; press A again to release it.
  4. For two finishers, press A when the first finishes, D when the second finishes, then A to show the second time.
  5. When it is stopped, press A to reset it to zero.
  6. Hold C for at least one second to go back to the Timekeeping Mode.

Good to know

It counts in 1/100 seconds for the first hour, then in seconds, up to 23 hours 59 minutes 59 seconds.

From Casio's guide, page 18

Countdown timer

  1. Press C until the Timer Mode (TR) shows, after the Stopwatch Mode.
  2. If a countdown is running, pause it with D and press A to reset it to its start time.
  3. Hold A for at least two seconds: the hour digits flash.
  4. Use B and D to set the hours (hold for fast), press C for the minutes and C again for the seconds, setting each the same way.
  5. Press A to exit the setting screen.
  6. Press D to start; press D again to pause and resume. When it is paused, press A to reset it to the start time.
  7. Hold C for at least one second to go back to the Timekeeping Mode.

Good to know

The start time is set in seconds up to 24 hours; set 0:00 00 for 24 hours.

At zero it beeps for 10 seconds; press any button to stop it. It does not beep when the battery is low.

You can also set the start time with the CASIO WATCHES app.

From Casio's guide, page 19

Reset the settings

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press C twice: the seconds flash.
  3. Hold B for at least six seconds and release it when ALL stops flashing.

Good to know

This returns the watch settings, stopwatch, timer and alarms to their factory defaults.

It also deletes the pairing information, so the watch is unpaired from the phone.

From Casio's guide, page 21

Module 3509 specs

Type
quartz
Power
Approx. battery life: 3 years on CR2016 · other watches that take CR2016
Accuracy
±15 seconds per month (with no mobile link function)
Functions
World time, Stopwatch, Timer, Alarm/hourly time signal, Light, Light color, Calendar, Mute feature, 12/24-hour format, Date/month display swapping, Day display
Manual
Casio's operation guide for module 3509

Watches with the 3509