Casio 3725 Operation Manual Download Page 2

Operation Guide 3725 3726

2

Signal reception is normally better at night than during the day.

Time calibration signal reception takes from two to seven minutes, but in some cases
it can take as long as 14 minutes. Take care that you do not perform any button
operations or move the watch while time calibration signal reception is in progress.

This watch is designed to receive the time calibration signal transmitted from Rugby,
England and the signal from Mainflingen, Germany. Signal reception is possible
within the area represented by a circle with a radius of about 1,500 kilometers.

At distances further than about 500 kilometers from a transmitter, signal reception
may not be possible during certain times of year or times of day. Radio interference
may also cause problems with reception.

See the information under “Signal Reception Troubleshooting” if you experience
problems with time calibration signal reception.

Rugby

Mainflingen

1,500 kilometers

500 kilometers

About Auto Receive

When auto receive is turned on, the watch automatically starts to receive the time
calibration signal when the time in the Timekeeping Mode reaches midnight, 1:00
a.m., 2:00 a.m., 3:00 a.m., and 4:00 a.m. each day (calibration times). The watch will
also perform an additional auto receive at 5:00 a.m. if none of the regularly scheduled
auto receive operations are successful.

Note

Auto receive is performed only if the watch is in the Timekeeping Mode or World
Time Mode when one of the calibration times is reached. It is not performed if a
calibration time is reached while an alarm is sounding, or while you are configuring
settings (while a setting is flashing).

Auto receipt of the calibration signal is designed to be performed early in the
morning, while you sleep (provided that the Timekeeping Mode time is set correctly).
Before going to bed for the night, remove the watch from your wrist, and put it in a
location where it can easily receive the signal.

When auto receive is turned on, the watch receives the calibration signal for two to
seven minutes everyday when the time in the Timekeeping Mode reaches each of
the five calibration times. Do not perform any button operation within seven minutes
before or after any of the five calibration times. Doing so can interfere with correct
calibration.

Remember that reception of the calibration signal depends on the digital time kept
by the Timekeeping Mode. Reception will be performed whenever the Timekeeping
Mode time reaches one of the five calibration times, regardless of whether or not the
Timekeeping Mode time is actually the correct time.

When two, three, four, or five receptions are successful, the watch uses the data of
the last reception for calibration. When only one reception is successful, the watch
uses the data of the successful reception.

About the Receiving Indicator

The receiving indicator shows the strength of the calibration signal being received. For
best reception, be sure to keep the watch in a location where signal strength is
strongest.

Even in an area where signal strength is strong, it takes about 10 seconds for signal
reception to stabilize enough for the receiving indicator to indicate signal strength.

Use the receiving indicator as a guide for checking signal strength and for finding the
best location for the watch during signal reception.

Receiving indicator

Weak

Strong

(Level 0)

(Level 3)

The Level 3 receiving indicator remains displayed in all modes following reception of
the time calibration signal and calibration of the watch’s time setting. The Level 3
receiving indicator is not displayed if signal reception was unsuccessful or after
manual adjustment of the current time setting.

The Level 3 receiving indicator indicates that at least one of the five calibration
signal receive operations was successful. Note, however, that the Level 3 receiving
indicator is cleared at 3:00 a.m. each day.

To perform manual receive

1. Place the watch on a stable surface so its top (12

o’clock side) is facing towards a window.

2. In the Timekeeping Mode, hold down 

D

 for about two

seconds until the watch beeps.

3. After you release 

D

, the bottom dial will alternate

between the current time and date, and the letters

RC!

. This indicates that signal reception is in

progress.

Receiving indicator

Time calibration signal reception normally takes from two to seven minutes, but in
some cases it can take as long as 14 minutes. Take care that you do not perform any
button operations or move the watch while time calibration signal reception is in
progress.

After signal reception is complete, the bottom dial changes to the last signal screen.

Note

To interrupt a reception and return to the Timekeeping Mode, press 

D

.

If reception is unsuccessful, the message 

ERR

 appears in the bottom dial for about

one or two minutes. After that, the watch returns to the Timekeeping Mode.

You can also clear the 

ERR

 message by pressing 

D

.

Configuring Auto Receive Settings

You can use the procedure in this section to configure the watch to receive the signal
of a specific transmitter, or to automatically receive from the transmitter whose signal
is strongest. You can also turn off auto receive, if you want.

Note that you can perform the following procedure only when 

LON

BER

, or 

PAR

is selected as your Home City.

To configure auto receive settings

1. In the Timekeeping Mode, press 

D

 to display the last

signal screen in the bottom dial.

The watch will automatically return to the Timekeeping
Mode if you do not perform any button operation for two
or three minutes after displaying the last signal screen.

2. Hold down 

A

 until the current auto receive setting

flashes in the bottom dial. This is the setting screen.

If the auto receive setting does not appear when you
hold down 

A

, it means that the city code currently

selected for the Home City is for an area that does not
support calibration signal reception. You cannot turn
auto receive on or off in this case.

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Setting status

3. Use 

D

 to cycle through the settings shown below, until the one you want to use is

displayed in the bottom dial.

DCF

OFF

A

vtA

 : Auto receive on. The watch automatically selects the transmitter whose

signal is strongest. Signal reception can take up to 14 minutes when this
option is selected.

DCF

 : Auto receive on for reception of the Mainflingen signal.

M

SF

 : Auto receive on for reception of the Rugby signal.

OFF

 : Auto receive off.

For details about transmitters, see “Transmitters”.

4. Press 

A

 to exit the setting screen.

To return to the Timekeeping Mode from the last signal screen, press 

D

.

For information about city codes that support signal reception, see “To set your
Home City”.

Note

Manual receive operations are also performed based on the transmitter setting
(

A

vtA

DCF

M

SF

) you select above.

If auto receive is turned off, performing a manual receive operation automatically
receives the signal that is strongest.

Problem

Cannot perform
manual receive.

Auto receive is
turned on, but
the Level 3
receiving
indicator does
not appear.

Time setting is
incorrect
following signal
reception.

Probable Cause

The watch is not in the Timekeeping
Mode.

Your current Home City is not one of the
following city codes: 

BER

PAR

, or

LON

.

You changed the time setting manually.

The watch was not in the Timekeeping
or World Time Mode, or you were
performing some button operation
during the auto receive.

Even if reception is successful, the
Level 3 receiving indicator disappears
every day at 3 a.m.

Time data (hour, minutes, seconds) only
was received during the last reception.
The Level 3 receiving indicator appears
only when time data and date data
(year, month, day) are both received.

If the time is one hour off, the DST
setting may be incorrect.

The Home City code setting is not
correct for the area where you are using
the watch.

What you should do

Enter the Timekeeping Mode
and try again.

Select 

BER

PAR

, or 

LON

as your Home City.

Select the appropriate
transmitter setting for your
current location.

Perform manual receive or
wait until the next auto signal
receive is performed.

Check to make sure the
watch is in a location where it
can receive the signal.

Change the DST setting to
Auto DST.

Select the correct Home City
code.

Signal Reception Troubleshooting

Check the following points whenever you experience problems with signal reception.

For further information, see “Important!” under “Time Calibration Signal Reception”
and “Radio-controlled Timekeeping Precautions”.

World Time

The World Time Mode digitally shows the current time in
30 cities (29 time zones) around the world.

Pressing 

A

 in the World Time Mode causes the

applicable city code to appear in the bottom dial for
about one second.

If the current time shown for a city is wrong, check your
Home City time settings and make the necessary
changes.

The watch will perform a signal reception even if it is in
the World Time Mode when a calibration time is
reached. If this happens, the World Time Mode time
settings will be adjusted in accordance with the
Timekeeping Mode’s Home City time.

All of the operations in this section are performed in the
World Time Mode, which you enter by pressing 

C

.

P

City code

Current
time in
selected
city

Mode indicator

To view the time in another city

While in the World Time Mode, press 

D

 to scroll through the city codes (time zones)

to the east or 

B

 to scroll to the west.

For full information on city codes, see the “City Code Table”.

Summary of Contents for 3725

Page 1: ...tion see To set your Home City below When using the watch in an area that is outside of the range of the transmitters in Rugby and Mainflingen you need to manually adjust the time as required See Timekeeping for information about manual settings The analog time of this watch is synchronized with the digital time Because of this the analog time setting is automatically adjusted whenever you change ...

Page 2: ...tom dial changes to the last signal screen Note To interrupt a reception and return to the Timekeeping Mode press D If reception is unsuccessful the message ERR appears in the bottom dial for about one or two minutes After that the watch returns to the Timekeeping Mode You can also clear the ERR message by pressing D Configuring Auto Receive Settings You can use the procedure in this section to co...

Page 3: ...epeat on and off below for details on the auto repeat setting 4 Press A to exit the setting screen Minutes Auto repeat To use the countdown timer Press D while in the Countdown Timer Mode to start the countdown timer When the end of the countdown is reached and auto repeat is turned off the alarm sounds for 10 seconds or until you stop it by pressing any button The countdown time is automatically ...

Page 4: ...on Beeper tone Coordination between digital and analog timekeeping Time calibration signal reception After some time battery power will recover and the recover indicator will disappear indicating that the above functions are enabled again Charging Precautions Certain charging conditions can cause the watch to become very hot Avoid leaving the watch in the areas described below whenever charging it...

Page 5: ... left for a certain period in an area where it is dark The table below shows how watch functions are affected by Power Saving Power saving indicator Wearing the watch inside the sleeve of clothing can cause it to enter the sleep state The watch will not enter the sleep state between 6 00 AM and 10 59 PM If the watch is already in the sleep state when 6 00 AM arrives however it will remain in the s...

Page 6: ...reas and can run down the batteries Illumination may not turn on if the face of the watch is more than 15 degrees above or below parallel Make sure that the back of your hand is parallel to the ground Illumination turns off after the preset illumination duration see To set the current digital time and date manually even if you keep the watch pointed towards your face Static electricity or magnetic...

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