Watch Catalog

Casio module 3501

Solar powered module. 3501 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 3501

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 until the setting you want flashes. The order is: Home City, summer time, seconds, hour, minutes, year, month, day, 12/24-hour format, date format, day of the week language, button tone, light duration, auto time adjustment, then Power Saving.
  3. On the seconds, press D to reset them to 00.
  4. On any other setting, press B or D to change it (hold for fast).
  5. Press A to leave the setting screen.

Good to know

Resetting the seconds between 30 and 59 adds one minute.

The watch sets itself from a time signal or, while paired, from the CASIO WATCHES phone app: it connects to the phone at around 12:30 a.m., 6:30 a.m., 12:30 p.m. and 6:30 p.m. Setting the time by hand is for when it cannot connect.

To take the time from the phone now, move the phone close to the watch and press D in the Timekeeping Mode: TIME flashes, then OK shows.

To receive the time signal now, place the watch near a window and hold D for at least two seconds until RCVD flashes. Reception can take from two to 10 minutes, or as long as 20 minutes.

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

12/24-hour format: press C eight times from the Home City, then D to switch between 12H and 24H.

In any mode, hold C for at least one second to go back to the Timekeeping Mode.

From Casio's guide, page 18

Summer time (DST)

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press C once: the summer time setting flashes.
  3. Press D to choose AUTO (switches between standard and summer time by itself), OFF (standard time) or ON (summer time).
  4. Press A to leave the setting screen.

Good to know

The factory setting for all cities is AUTO; in many cases AUTO works without switching by hand.

DST shows while the watch shows summer time.

From Casio's guide, page 18

Home City

  1. In the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  2. Press B or D to change the Home City (hold for fast).
  3. Press A to leave the setting screen.

Good to know

The watch will not show the correct time if the Home City setting is wrong for your location.

In the World Time Mode, press A and B at the same time to swap the Home City and the World Time city, for example when you arrive in another time zone.

World Time cities can also be picked in the CASIO WATCHES app, from about 300 cities.

From Casio's guide, page 17

Set an alarm

  1. In the Timekeeping Mode, press C until the Alarm Mode shows (AL), after the World Time Mode.
  2. Press D until the alarm you want shows, 1 to 4 or SNZ (the snooze alarm).
  3. Hold A for at least two seconds and release it when the hour digits flash.
  4. Press B or D to set the hour; mind the P indicator for p.m.
  5. Press C: the minutes flash. Press B or D to set them.
  6. Press A to leave the setting screen: the alarm indicator shows while the alarm is on.
  7. To switch an alarm on or off, select it in the Alarm Mode with D and press A: ON or OFF shows.

Good to know

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

The snooze alarm sounds up to seven times, at five-minute intervals.

Hourly time signal: in the Alarm Mode, press D until SIG shows and press A to switch it on or off.

The alarm is muted when the battery is low or the watch is at Level 2 power saving.

Alarms can also be set in the CASIO WATCHES app.

From Casio's guide, page 20

Light

  1. Press B to light up the display.
  2. Auto Light (the display lights when you angle the watch 40 degrees or more towards you): in the Timekeeping Mode, hold B for at least three seconds to switch it on or off; LT shows while it is on.
  3. To change the duration: in the Timekeeping Mode, hold A for at least two seconds and release it when the Home City name shows.
  4. Press C 12 times: LIGHT shows.
  5. Press D to choose 2 (two seconds) or 4 (four seconds), then A to leave.

Good to know

The light turns off when an alarm starts to sound, and does not work while the watch receives the time signal.

Frequent use of the light runs down the battery.

Auto Light does not work while CHG shows; it may not work when the watch is 15 degrees or more from horizontal.

From Casio's guide, page 8

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: KEY♪ or MUTE flashes.
  3. Press D to choose KEY♪ (tone on) or MUTE (tone off).
  4. Press A to leave the setting screen.

Good to know

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

From Casio's guide, page 25

Stopwatch

  1. In the Timekeeping Mode, press C until the Stopwatch Mode shows (ST).
  2. Press D to start, D to stop, and D again to carry on.
  3. For a split time, press A while it runs (SPL shows); press A again to release the split.
  4. When it is stopped, press A to reset it to zero.

Good to know

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

For two finishers: start with D, press A at the first finisher and D at the second; the first time shows, press A to see the second, and A again to reset.

From Casio's guide, page 22

Countdown timer

  1. In the Timekeeping Mode, press C until the Timer Mode shows (TR).
  2. If a countdown is running, press D to pause it, then A to reset it to its start time.
  3. Hold A for at least two seconds: the hours flash. Press B or D to set them.
  4. Press C: the minutes flash. Press B or D to set them.
  5. Press C: the seconds flash. Press B or D to set them.
  6. Press A to leave the setting screen.
  7. Press D to start, D to pause, D to carry on; when paused, press A to reset it to the start time.

Good to know

The start time can be 1 second to 24 hours; set 0:00 00 for 24 hours.

At zero a beeper sounds for 10 seconds; press any button to stop it. It is muted when the battery is low.

The timer can also be set in the CASIO WATCHES app.

From Casio's guide, page 23

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 seven seconds and release it when ALL stops flashing.

Good to know

This returns the watch settings, reminders, 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 26

Module 3501 specs

Type
solar
Power
Tough Solar (Solar powered)
Accuracy
±15 seconds per month (with no signal calibration and mobile link function)
Functions
World time, Stopwatch, Timer, Alarm/hourly time signal, Light, Light color, Calendar, Mute feature, Energy saving feature, Battery display/alert, Run time, 12/24-hour format, Date/month display swapping, Day display, Time adjustment details
Manual
Casio's operation guide for module 3501

Watches with the 3501