Operation Guide 2608 2638 2688
1
MO0306-EA
Getting Acquainted
Congratulations upon your selection of this CASIO watch. To get the most out of your
purchase, be sure to carefully read this manual and keep it on hand for later reference
when necessary.
• This watch does not have a time zone that corresponds to the Greenwich
Mean Time differential of –3.5 hours. Because of this, the radio-controlled
timekeeping and World Time functions will not display the correct time for
Newfoundland, Canada.
Expose the watch to bright light to charge its battery before using it.
You can use this watch even as its battery is being charged by exposure to bright
light.
• Be sure to read “Battery” of this manual for important information you need
to know when exposing the watch to bright light.
If the display of the watch is blank...
If the sleep indicator (S /SLEEP ) is on the display, it
means that the display is blank because the watch’s
Power Saving function has shut it to conserve power.
Power Saving automatically turns off the display and
enters a sleep state whenever your watch is left in an
area where it is dark for a certain period.
• The initial factory default setting is Power Saving on.
• The watch recovers from the sleep state if you move it
to a well-lit area
*
, if you press any button, or if you
angle the watch towards your face for reading.
*
It can take up to two seconds for the display to turn on.
• See “Power Saving Function” for more information.
Sleep indicator
General Guide
• Press C to change from mode to mode.
• In any mode, press L to illuminate the display.
Stopwatch Mode
Timekeeping Mode
Alarm Mode






Press C.


World Time Mode
Time Recorder Mode


Radio-controlled Atomic Timekeeping
This watch receives a time calibration signal and updates
its time setting accordingly. The time calibration signal
includes both Standard Time and Daylight Saving Time
(summer time) data.
• This watch is designed to pick up the time calibration
signal transmitted from Fort Collins, Colorado (USA).
Reception is possible within North America
*
.
*
The term “North America” in this User’s Guide refers to the
area that consists of Canada, the continental United States,
and Mexico.
Current Time Setting
This watch automatically adjusts its time setting in accordance with a time calibration
signal. You can also perform a manual procedure to set the time and date, when
necessary.
• The first thing you should do after purchasing this watch is to set your Home City,
which is the city where you will normally use the watch. For more information, see
“To set your Home City” below.
• When using the watch outside of the range of the transmitter in Fort Collins, you
need to manually adjust the time as required. See “Timekeeping” for information
about manual settings.
To set your Home City
1. In the Timekeeping Mode, hold down A until the city
code starts to flash, which indicates the setting screen.
2. Use D(east) and B(west) to select the city code you
want to use as your Home City.
• The following are the city codes for major cities in
North America.
LAX(P (Pacific) indicator):
Los Angeles, San Francisco, Las Vegas, Seattle,
Vancouver, Tijuana
DEN(M (Mountain) indicator):
Denver, El Paso, Edmonton, Culiacan
CHI(C (Central) indicator):
Chicago, Houston, Dallas/Fort Worth, New Orleans,
Winnipeg, Mexico City
NYC(E (Eastern) indicator):
New York, Detroit, Miami, Boston, Montreal
• Note that this watch does not have a city code that
corresponds to Newfoundland.
3. Press A twice to exit the setting screen.
• The first press of A displays the 12/24-hour setting
screen. Pressing A again exits the setting screen.
Important!
• Normally, your watch should show the correct time as soon as you select your Home
City code. If it does not, it should adjust automatically after the next auto receive
operation (in the middle of the night). You can also perform manual receive or you
can set the time manually.
• If you are in an area that does not use Daylight Saving Time (summer time), turn off
the DST setting.
Time Calibration Signal Reception
There are two different methods you can use to receive the time calibration signal:
auto receive and manual receive.
Day of week
Month – Day
Hour : Minutes Seconds
PM
indicator
City code
E/C/M/P indicator
• Auto Receive
With auto receive, the watch automatically picks up the time calibration signal four
times a day at 2:00 a.m., 3:00 a.m., 4:00 a.m., and 5:00 a.m. For more information,
see “About Auto Receive”.
• Manual Receive
Manual receive lets you start a time calibration receive operation with the press of a
button. For more information, see “To perform manual receive”.
Important!
• When getting ready to receive the time calibration signal, position the watch as
shown in the nearby illustration, with its 12 o’clock side facing towards a window.
Make sure there are no metal objects nearby.
Resin Band Metal Band
Inside or
among
buildings
Inside a
vehicle
Near
household
appliances or
office
equipment,
or a mobile
phone
Near a
construction
site, airport, or
other sources
of electrical
noise
Near high-
tension
power lines
Among or
behind
mountains
• The watch should not be on its side or facing the wrong way.
• Proper signal reception can be difficult or even impossible under the conditions
listed below.
• Signal reception is normally better at night than during the day.
• Time calibration signal reception takes from two to six minutes, but in some cases it
can take as long as 12 minutes. Take care that you do not perform any button
operations or move the watch during this time.
About This Manual
• The operational procedures for Modules 2608, 2638 and 2688 are identical. All of
the illustrations in this manual show Module 2608.
• Button operations are indicated using the letters shown in the illustration.
• Each section of this manual provides you with the information you need to perform
operations in each mode. Further details and technical information can be found in
the “Reference” section.
Module 2608
(Light)
Module 2638
(Light)
Module 2688
(Light)
• Under good reception conditions, signal reception is possible within a radius of
about 2,000 miles (3,000 kilometers) from the Fort Collins transmitter.
2,000 miles
Fort Collins
600 miles
Operation Guide 2608 2638 2688
2
• At distances further than about 600 miles (1,000 kilometers) from the transmitter,
signal reception may not be possible during certain times of year or times of day.
Radio interferance may also cause problems with reception.
• See the information under “Signal Receive Troubleshooting” if you experience
problems with time calibration signal reception.
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 2:00 a.m., 3:00
a.m., 4:00 a.m., and 5:00 a.m. each day (calibration times).
Note
• The auto receive operation 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 settings are flashing on the display).
• 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
six minutes everyday when the Timekeeping Mode time reaches each of the
calibration times. Do not perform any button operation within six minutes before or
after any one of the calibration times. Doing so can interfere with correct calibration.
• Remember that reception of the calibration signal depends on the time kept in the
Timekeeping Mode. The receive operation will be performed whenever the display
shows any one of the calibration times, regardless of whether or not the
Timekeeping Mode time is actually the correct time.
• When two, three, or four 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 receive operations.
• Following reception of the time calibration signal and calibration of the watch’s time
setting, the Level 4 receiving indicator will remain on the display in all modes. The
Level 4 receiving indicator will not be displayed if signal reception was unsuccessful
or after you adjust the current time setting manually.
• The Level 4 receiving indicator is displayed only when the watch is able to
successfully receive both time and date data. It does not appear when only time
data is received.
• The Level 4 receiving indicator indicates that at least one of the auto calibration
signal receive operations was successful. Note, however, that the Level 4 receiving
indicator is cleared from the display 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.
• Release D and the message RC! appears to indicate
that signal reception has started.
• Time calibration signal reception takes from two to six
minutes. Take care that you do not perform any button
operations or move the watch during this time.
• After signal reception is complete, the display of the
watch changes to the Last Signal screen.
Note
• To interrupt a receive operation and return to the Timekeeping Mode, press D.
• If the receive operation is unsuccessful, the message ERR appears on the display
for about one or two minutes. After that, the watch returns to the Timekeeping Mode.
• You can also change from the Last Signal or ERR screen to the normal
timekeeping screen by pressing D.
To turn auto receive on and off
1. In the Timekeeping Mode, hold down A until the city
code starts to flash, which indicates the setting screen.
2. Press C twice to move the flashing to the auto receive
on/off setting.
3. Press D to toggle auto receive on (ON) and off (OF).
• If the current Home City setting is a city code that
does not support signal receive, “xx” appears in
place of the on/off indicator. This means you cannot
turn auto receive on or off.
4. Press A twice to exit the setting screen.
• For information about city codes that support signal
receive, see “To set your Home City”.
To display the Last Signal screen
In the Timekeeping Mode, press D to display the Last Signal screen (indicated by
GET). The Last Signal screen shows the date and time of the last successful time
calibration signal reception.
Receiving indicator
On/off status
l
l
l
l
l
l
l
l
l
l l
l l l l l
l l l l
l l l l l l lll
l
l
l
l
l
l
l
l
Signal Receive Troubleshooting
Check the following points whenever you experience problems with calibration signal
reception.
Last Signal Screen


Press D.
Day of week
Receive time
Month – Day
Hour : Minutes Seconds
PM
indicator


Receive date
Problem
Cannot perform
manual receive.
Auto receive is
turned on, but
the Level 4
receiving
indicator does
not appear on
the display.
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:
LAX, DEN, CHI, or NYC.
• You changed the time setting manually.
• The watch was not in the Timekeeping
or World Time Mode, or you performed
some button operation during the auto
receive operation.
• Even if receive is successful, the Level
4 receiving indicator disappears every
day at 3 am.
• Time data (hour, minutes, seconds) only
was received during the last receive
operation. The Level 4 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 LAX, DEN, CHI, or
NYC as your Home City.
• Perform manual signal receive
or wait until the next auto
signal receive operation 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.
• For further information, see “Important!” under “Time Calibration Signal Reception”
and “Radio-controlled Atomic Timekeeping Precautions”.
World Time
World Time shows the current time in 30 cities (29 time
zones) around the world.
• For full information on city codes, see the “City Code
Table”.
• The current time for all city codes in the World Time
Mode is calculated in accordance with the Greenwich
Mean Time (GMT) differential for each city, based on the
your Home City time setting.
• All of the operations in this section are performed in the
World Time Mode, which you enter by pressing C.
To view the time for another city code
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.
• If the current time shown for a city is wrong, check your Timekeeping Mode time and
Home City settings and make the necessary changes.
To toggle a city code time between Standard Time and Daylight Saving Time
1. In the World Time Mode, use B and D to display the
city code (time zone) whose Standard Time/Daylight
Saving Time setting you want to change.
2. Hold down A to toggle Daylight Saving Time (DST
indicator displayed) and Standard Time (DST indicator
not displayed).
• The DST indicator is on the display whenever you
display a city code for which Daylight Saving Time is
turned on.
• Note that the DST/Standard Time setting affects only the
currently displayed city code. Other city codes are not
affected.
• Daylight Saving Time (DST) advances the time setting
by one hour from Standard Time. Remember that not all
countries or even local areas use Daylight Saving Time.
• The watch will perform a signal receive operation 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 Home
City time.
Current time in the
selected city code
Home city time
City code
DST indicator
Module 2608
Module 2638
Module 2688
DST indicator
Time Recorder
The Time Recorder lets you store up to 30 records of the
current time (month, day, hour, minutes, seconds, and
DST on/off setting) with the touch of a button. One way
you can use the Time Recorder is to record the start time
and the end time of a particular event.
To record a Time Recorder time
In the Timekeeping Mode, hold down B to record the
Home City time (month, day, hour, minutes, seconds, and
DST on/off setting).
• The recorded time flashes for about two seconds, and
then it is assigned a record number. After that, the
Timekeeping Mode screen appears.
• Records are assigned numbers sequentially from #01
through #30.
• Storing a new time record when there are already 30
records stored in memory automatically deletes record
#01, shifts the remaining records upwards by 1, and
stores the new record as #30.
Time record number
Recorded time
(Hour : Minutes seconds)
Recorded date
(Month–Day)
Strong
Receiving indicator
Weak
(Level 1)
Module 2608
Module 2638
Modules 2608,
2638, and 2688
(Level 4)
Operation Guide 2608 2638 2688
3
To recall Time Recorder times
In the Time Recorder Mode, use D (+) and B (–) to scroll through times stored in
memory.
• If you recorded a new Time Recorder time since you last entered the Time Recorder
Mode, the newest record appears first. If you have not recorded a new time, the
record you were viewing when you last exited the Time Recorder Mode appears
first.
To delete all Time Recorder times
In the Time Recorder Mode, hold down A to delete all Time Recorder times.
Alarms
The Alarm Mode gives you a choice of four one-time
alarms and one snooze alarm.
Also use the Alarm Mode to turn the Hourly Time Signal
(SIG) on and off.
• There are five alarms numbered AL1 through AL4,
and SNZ. You can configure SNZ as a snooze alarm
only. Alarms AL1 through AL4 can be used as one-
time alarms only.
• Alarm settings (and Hourly Time Signal settings) are
available in the Alarm Mode, which you enter by
pressing C.
To set an alarm time
1. In the Alarm Mode, use D to scroll through the alarm
screens until the one whose time you want to set is
displayed.
2. After you select an alarm, hold down A until the hour
setting of the alarm time starts to flash, which indicates
the setting screen.
• This operation automatically turns on the alarm.
3. Use C to move the flashing between the hour and
minute settings.
4. While a setting is flashing, use D (+) and B (–) to
change it.
5. Press A to exit the setting screen.
• When setting the alarm time using the 12-hour format,
take care to set the time correctly as a.m. (A indicator)
or p.m. (P indicator).
Alarm Operation
The alarm tone sounds at the preset time for 10 seconds, regardless of the mode the
watch is in. In the case of the snooze alarm, the alarm operation is performed a total
of seven times, every five minutes, or until you turn the alarm off.
• Pressing any button stops the alarm tone operation.
• Performing any one of the following operations during a 5-minute interval between
snooze alarms cancels the current snooze alarm operation.
Displaying the Timekeeping Mode setting screen
Displaying the snooze alarm setting screen
To test the alarm
In the Alarm Mode, hold down B to sound the alarm.
To turn an alarm on and off
1. In the Alarm Mode, use D to select an alarm.
2. Press B to toggle it on and off.
• Turning on a one-time alarm (AL1, AL2, AL3,
AL4) displays the alarm on indicator on its Alarm Mode
screen. Turning on the snooze alarm (SNZ) displays
the alarm on indicator and snooze alarm indicator on its
Alarm Mode screen.
• In all modes, the alarm on indicator is shown for any
alarm that is currently turned on. When the snooze
alarm is on, the snooze alarm indicator is displayed in
all modes.
• The alarm on indicator flashes while the alarm is
sounding.
• The snooze alarm indicator flashes during the 5-minute
intervals between alarms.
To turn the Hourly Time Signal on and off
1. In the Alarm Mode, use D to select the Hourly Time
Signal (SIG).
2. Press B to toggle it on (Hourly Time Signal on
indicator displayed) and off (Hourly Time Signal on
indicator not displayed).
• The Hourly Time Signal on indicator is displayed in all
modes when the Hourly Time Signal is turned on.
Alarm time (Hour : Minutes)
Alarm number
Home city time
AL1
AL2
AL3
SIG
SNZ
AL4
Module 2688
Hourly time signal
on indicator
Module 2608
Module 2638
Module 2688
1/100 second
Hours
Home city time
Seconds
Minutes
D
Start
Stop
Elapsed Time
➤
Re-start
Clear
D
➤
Stop
D
➤D
➤B
Split Time
D
Start
Split
➤
Split release
Clear
B
➤
Stop
B
➤D
➤B
Two Finishes
D
Start
Split
➤
Stop
Clear
B
➤
Split release
D
➤B
➤B
First runner
finishes.
Display time of
first runner.
Second runner
finishes.
Display time of
second runner.
To measure times with the stopwatch
(SPL/ SPL displayed)
Backlight
The backlight uses an EL (electro-luminescent) panel that
causes the entire display to glow for easy reading in the
dark. The watch’s auto light switch automatically turns on
the backlight when you angle the watch towards your face
in the dark.
• The auto light switch must be turned on (indicated by
the auto light switch on indicator) for it to operate.
• See “Backlight Precautions” for other important
information about using the backlight.
To turn on the backlight manually
In any mode, press L to illuminate the display for about
one second.
• The above operation turns on the backlight regardless
of the current auto light switch setting.
About the Auto Light Switch
Turning on the auto light switch causes the backlight to turn on for about one second,
whenever you position your wrist as described below in any mode. Note that this
watch features a “Full Auto EL Light,” so the auto light switch operates only when
available light is below a certain level. It does not turn on the backlight under bright
light.
Moving the watch to a position that is parallel to the ground and then tilting it
towards you more than 40 degrees causes the backlight to turn on.
Warning!
• Always make sure you are in a safe place whenever you are reading the
display of the watch using the auto light switch. Be especially careful when
running or engaged in any other activity that can result in accident or injury.
Also take care that sudden illumination by the auto light switch does not
surprise or distract others around you.
• When you are wearing the watch, make sure that its auto light switch is turned
off before riding on a bicycle or operating a motorcycle or any other motor
vehicle. Sudden and unintended operation of the auto light switch can create
a distraction, which can result in a traffic accident and serious personal injury.
To turn the auto light switch on and off
In any mode, hold down L for about two seconds to toggle the auto light switch on
(auto light switch on indicator displayed) or off (auto light switch on indicator not
displayed).
• The auto light switch on indicator is on the display in all modes while the auto light
switch is turned on.
Battery
This watch is equipped with a solar cell and a rechargeable battery (secondary
battery) that is charged by the electrical power produced by the solar cell. The
illustration shown below shows how you should position the watch for charging.
Example: Orient the watch so its face
is pointing at a light source.
• Note that charging efficiency drops
when any part of the solar cell is
blocked by clothing, etc.
• The illustration shows how to position
a watch with a resin band.
Auto light switch on indicator
Module 2608
Module 2638
Module 2688
Solar cell
Stopwatch
The stopwatch lets you measure elapsed time, split times,
and two finishes.
• The display range of the stopwatch is 23 hours, 59
minutes, 59.99 seconds.
• The stopwatch continues to run, restarting from zero
after it reaches its limit, until you stop it.
• Exiting the Stopwatch Mode while a split time is frozen
on the display clears the split time and returns to
elapsed time measurement.
• The stopwatch measurement operation continues even
if you exit the Stopwatch Mode.
• All of the operations in this section are performed in the
Stopwatch Mode, which you enter by pressing C.
Alarm on indicator
Module 2638
Snooze on indicator
Module 2608
Alarm on indicator
More than
40°
Parallel to
ground
Operation Guide 2608 2638 2688
4
Important!
• Storing the watch for long periods in an area where there is no light or wearing it in
such a way that it is blocked from exposure to light can cause rechargeable battery
power to run down. Be sure that the watch is normally exposed to bright light
whenever possible.
• This watch employs a solar cell that converts light into electricity that charges a built-
in rechargeable battery. Normally, the rechargeable battery should not need
replacement, but after very long use over a number of years, the rechargeable
battery may lose its ability to achieve a full charge. Should you notice problems with
getting the rechargeable battery to a full charge, contact your dealer or CASIO
distributor about having the rechargeable battery replaced.
• The rechargeable battery should be replaced with a CASIO-specified CTL1616
battery only. Other rechargeable batteries can cause damage to the watch.
• All data stored in memory is deleted, and the current time and all other settings
return to their initial factory defaults whenever battery power drops to Level 4 and
when you have the battery replaced.
• Turn on the watch’s Power Saving function and keep it in an area normally exposed
to bright light when storing it for long periods. This helps to keep the rechargeable
battery from going dead.
Battery Power Indicator
The battery power indicator on the display shows you the current status of the
rechargeable battery’s power.
Battery power
indicator
Recover
indicator
Level
1
2
3
4
Battery Power Indicator
Charge Soon Alert
Function Status
All functions enabled.
All functions enabled.
Beeper tone, backlight,
calibration signal
reception, display, and
buttons are disabled.
All functions, including
timekeeping, are
disabled.
Module 2608
2638
2688
• The Level 3 charge warning indicator tells you that battery power is very low, and
that exposure to bright light for charging is required as soon as possible.
• At Level 4, all functions are disabled and settings return to their initial factory
defaults. Functions are enabled once again after the rechargeable battery is
charged, but you need to set the time and date after the battery reaches Level 3
from Level 4. You will not be able to configure any of the other settings until the
battery reaches Level 2 after dropping to Level 4.
• Leaving the watch in direct sunlight or some other very strong light source can
cause the battery power indicator to temporarily show a reading that is actually
higher than the battery level. The correct battery power indicator should appear after
a few minutes.
• If you use the backlight or the alarms a number of times during a short period, the
recover indicator (R /RECOVER ) appears on the display and the following
operations become disabled until battery power recovers.
Backlight
Beeper tone
Calibration reception
After some time, battery power will recover and the recover indicator (R /
RECOVER ) 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 its rechargeable battery.
Also note that allowing the watch to become very hot can cause its liquid crystal
display to black out. The appearance of the LCD should become normal again when
the watch returns to a lower temperature.
Warning!
Leaving the watch in bright light to charge its rechargeable battery can cause it
to become quite hot. Take care when handling the watch to avoid burn injury.
The watch can become particularly hot when exposed to the following
conditions for long periods.
• On the dashboard of a car parked in direct sunlight
• Too close to an incandescent lamp
• Under direct sunlight
Charging Guide
After a full charge, timekeeping remains enabled for up to about six months, while the
watch is used under the conditions described below.
Operating Conditions
• Watch is not exposed to light
• Display on 18 hours per day, sleep state 6 hours per day
• 1 backlight operation (1.5 seconds) per day
• 10 seconds of alarm operation per day
• 4 times calibration reception per day
Charge Times
Exposing the watch to light for the periods shown below each day restores the power
used by the above operating conditions.
Exposure Level (Brightness)
Approximate
Exposure Time
Outdoor Sunlight (50,000 lux)
5 minutes
Sunlight Through a Window (10,000 lux)
24 minutes
Daylight Through a Window on a Cloudy Day (5,000 lux)
48 minutes
Indoor Fluorescent Lighting (500 lux)
8 hours
• Stable operation is promoted by frequent charging.
Recovery Times
The table below shows the amount exposure that is required to take the battery from
one level to the next.
Exposure Level
(Brightness)
Outdoor Sunlight
(50,000 lux)
Sunlight Through a
Window (10,000 lux)
Daylight Through a
Window on a Cloudy
Day (5,000 lux)
Indoor Fluorescent
Lighting (500 lux)
Approximate Exposure Time
Level 4
Level 3
Level 2
Level 1
1 hour
14 hours
3 hours
3 hours
70 hours
14 hours
5 hours
143 hours
28 hours
57 hours
------------
------------






• The above exposure time values are all for reference only. Actual required exposure
times depend on lighting conditions.
Timekeeping
Use the Timekeeping Mode to set and view the current time and date. This section
also explains how to manually set the current date and time.
• The watch is equipped with a Time Recorder feature that lets you record the current
Home City time (month, day, hour, minutes, seconds, and DST on/off setting) with
the touch of a button. See “To record a Time Recorder time” for more information.
• All of the operations in this section are performed in the Timekeeping Mode, which
you can enter by pressing C.
Setting the Time and Date Manually
Make sure you select your Home City code before you change the current time and
date settings. World Time Mode times are all displayed in accordance with the
Timekeeping Mode settings. Because of this, World Time Mode times will not be
correct if you do not select the proper Home City code before setting the time and
date in the Timekeeping Mode.
To set the current time and date manually
1. In the Timekeeping Mode, hold down A until the city
code starts to flash, which indicates the setting screen.
2. Press A or C to move the flashing in the sequence
shown below to select other settings.
Last Signal Screen


Press D.
Day of week
Receive time
Month – Day
Hour : Minutes Seconds
PM
indicator


Receive date
City/Auto receive
Settings
Time/Date/Power
Saving Settings
Auto
Receive
DST
City Code
Seconds
Hour
Minutes
12/24-Hour
Format
Day
Month
Year
Power Saving
on/off
/ Press A.
Press C.
C
A
C
City code
3. When the setting you want to change is flashing, use B and/or D to change it as
described below.
Screen:
To do this:
Change the city code
Cycle between Daylight Saving Time
(ON), Standard Time (OFF), and
Auto DST (AUTO)
Toggle between auto receive on
(ON) and off (OFF)
Do this:
Use D (east) and B (west).
Press D.
Press D.
City/Auto Receive Settings
• See “City Code Table” for a complete list of available city codes.
Screen:
To do this:
Toggle between 12-hour (12H) and
24-hour (24H) timekeeping
Reset the seconds to 00
Change the hour or minutes
Change the month, day, or year
Toggle the Power Saving on (ON)
and off (OFF)
Do this:
Press D.
Press D.
Use D (+) and B (–).
Use D (+) and B (–).
Press D.
Time/Date/Power Saving Settings
4. Use A to exit the setting screen.
• If a City/Auto Receive Setting screen is displayed, press A twice.
• If a Time/Date/Power Saving Setting screen is displayed, press A once.
Note
• Auto DST (AUTO) can be selected only while HNL, ANC, LAX, DEN, CHI, or
NYC is selected as the Home City code. For more information, see “Daylight Saving
Time (DST)” below.
• The auto receive setting is used for time calibration signal reception only. See
“About Auto Receive” for details.
Operation Guide 2608 2638 2688
5
Daylight Saving Time (DST)
Daylight Saving Time (summer time) advances the time setting by one hour from
Standard Time. Remember that not all countries or even local areas use Daylight
Saving Time.
The time calibration signal transmitted from Fort Collins includes both Standard Time
and DST data. When the Auto DST setting is turned on, the watch switches between
Standard Time and DST (summer time) automatically in accordance with the received
time signal.
• The default DST setting is Auto DST (AUTO) whenever you select HNL, ANC,
LAX, DEN, CHI, or NYC as your Home City code.
• If you experience problems receiving the time calibration signal in your area, it is
probably best to switch between Standard Time and Daylight Saving Time (summer
time) manually.
To change the Daylight Saving Time (summer time) setting
1. In the Timekeeping Mode, hold down A until the city code starts to flash, which
indicates the setting screen.
2. Press C and the DST setting screen appears.
3. Use D to cycle through the DST settings in the sequence shown below.
4. When the setting you want is selected, press A twice to exit the setting screen.
Reference
This section contains more detailed and technical information about watch operation.
It also contains important precautions and notes about the various features and
functions of this watch.
Auto Return Features
• If you leave the watch in the Time Recorder Mode or Alarm Mode for two or three
minutes without performing any operation, it automatically returns to the
Timekeeping Mode.
• If you leave a screen with flashing digits on the display for two or three minutes
without performing any operation, the watch automatically saves anything you have
input up to that point and exits the setting screen.
Data and Setting Scrolling
The B and D buttons are used in various modes and setting screens to scroll
through data on the display. In most cases, holding down these buttons during a scroll
operation scrolls through the data at high speed.
Initial Screens
When you enter the Alarm or World Time Mode, the data you were viewing when you
last exited the mode appears first.
Radio-controlled Atomic Timekeeping Precautions
• Strong electrostatic charge can result in the wrong time being set.
• Even when the watch is within the reception range of the transmitter, signal
reception is impossible if the signal is blocked by mountains or other geological
formations between the watch and signal source.
• Signal reception is affected by weather, atmospheric conditions, and seasonal
changes.
• The time calibration signal is bounced off the ionosphere. Because of this, such
factors as changes in the reflectivity of the ionosphere, as well as movement of the
ionosphere to higher altitudes due to seasonal atmospheric changes or the time of
day may change the reception range of the signal and make reception temporarily
impossible.
• Even if the time calibration signal is received properly, certain conditions can cause
the time setting to be off by up to one second.
• The current time setting in accordance with the time calibration signal takes priority
over any time settings you make.
• The watch is designed to automatically update the date and day of the week for the
period January 1, 2000 to December 31, 2099. Setting of the date by the time
calibration signal cannot be performed starting from January 1, 2100.
• This watch can receive signals that differentiate between leap years and non-leap
years.
• Though this watch is designed to receive both time data (hour, minutes, seconds)
and date data (year, month, day), certain signal conditions can limit reception to time
data only.
• Normally, the signal reception date shown by the Last Signal screen is the date data
included in the received time calibration signal. When only time data is received,
however, the Last Signal screen shows the date as kept in the Timekeeping Mode at
the time of signal reception.
• If you are in an area where proper time calibration signal reception is impossible, the
watch keeps time within ±15 seconds a month at normal temperature.
• If you have problems with proper time calibration signal reception or if the time
setting is wrong after signal reception, check your current city code, DST (summer
time), and auto receive settings. The following are the initial factory defaults for
these settings.
Auto DST (AUTO)
DST off (OFF)
DST on (ON)
Setting
City code
DST (summer time)
Auto receive
Initial Factory Default
NYC
(New York)
DST
(Auto switching)
AUTO
(Auto receive)
ON
Timekeeping
• The day of the week is automatically displayed in accordance with the date (year,
month, and day) settings.
• The year can be set in the range of 2000 to 2099.
• The watch’s built-in full automatic calendar makes allowances for different month
lengths and leap years. Once you set the date, there should be no reason to change
it except after you have the watch’s battery replaced or when battery power drops to
Level 4.
• The current time for all city codes in the Timekeeping Mode and World Time Mode is
calculated in accordance with the Greenwich Mean Time (GMT) differential for each
city, based on the your Home City time setting.
• GMT differential is calculated by this watch based on UTC
*
data.
*
The letters “UTC” stands for “Universal Time Coordinated,” which is the world-wide
scientific standard of timekeeping. It is based upon carefully maintained atomic
(cesium) clocks that keep accurate to within microseconds. Leap seconds are
added or subtracted as necessary to keep UTC in sync with the Earth’s rotation.
The reference point for UTC is Greenwich, England.
12-hour/24-hour Timekeeping Formats
The 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is also
applied in all other modes.
• With the 12-hour format, the P (PM) indicator appears on the display for times in the
range of noon to 11:59 p.m. and the A (AM) indicator appears for times in the range
of midnight to 11:59 a.m.
• With the 24-hour format, times are displayed in the range of 0:00 to 23:59, without
any indicator.
Power Saving Function
When turned on, the Power Saving function automatically enters a sleep state
whenever the watch is left in an area where it is dark for a certain period. The table
below shows how watch functions are affected by the Power Saving function.
• 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 sleep state.
To recover from the sleep state
Perform any one of the following operations.
• Move the watch to a well-lit area. It can take up to two seconds for the display to
turn on.
• Press any button.
• Angle the watch towards your face for reading.
To turn Power Saving on and off
1. In the Timekeeping Mode, hold down A. This causes
the city code to flash, which indicates the setting
screen.
2. Press A again.
3. Press C seven times until the Power Saving on/off
screen appears.
4. Press D to toggle Power Saving on (ON) and off
(OFF).
5. After the setting is the way you want, press A to exit
the setting screen.
• The Power Saving on indicator is on the display in all
modes while the Power Saving is turned on.
Backlight Precautions
• The electro-luminescent panel that provides illumination loses power after very long
use.
• The illumination provided by the backlight may be hard to see when viewed under
direct sunlight.
• The watch may emit an audible sound whenever the display is illuminated. This is
due to vibration of the EL panel used for illumination, and does not indicate
malfunction.
• The backlight automatically turns off whenever an alarm sounds.
• Frequent use of the backlight shortens the battery operating time.
Auto light switch precautions
• Wearing the watch on the inside of your wrist as well as movement or vibration of
your arm can cause the auto light switch to activate and illuminate the display. To
avoid running down the battery, turn off the auto light switch whenever engaging in
activities that might cause frequent illumination of the display.
• The backlight may not light 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.
• The backlight turns off in about one second, even if you
keep the watch pointed towards your face.
• Static electricity or magnetic force can interfere with
proper operation of the auto light switch. If the backlight
does not light, try moving the watch back to the starting
position (parallel with the ground) and then tilt it back
toward you again. If this does not work, drop your arm
all the way down so it hangs at your side, and then bring
it back up again.
• Under certain conditions, the backlight may not light
until about one second after you turn the face of the
watch towards you. This does not necessarily indicate
malfunction of the backlight.
• You may notice a very faint clicking sound coming from
the watch when it is shaken back and forth. This sound
is caused by mechanical operation of the auto light
switch, and does not indicate a problem with the watch.
Elapsed Time
in Dark
60 to 70 minutes
6 or 7 days
Display
Blank, with Sleep indicator (S /
SLEEP ) flashing
Blank, with Sleep indicator (S /
SLEEP ) not flashing
Operation
All functions enabled, except
for the display
Beeper tone, backlight, display,
and auto receipt of the
calibration signal are disabled.
l l l lll
l
l
l
ll
l
Power saving on
indicator
More than 15 degrees
too high
Operation Guide 2608 2638 2688
6
HONOLULU
ANCHORAGE
LOS ANGELES
DENVER
CHICAGO
NEW YORK
CARACAS
RIO DE JANEIRO
LONDON
PARIS
BERLIN
ATHENS
CAIRO
JERUSALEM
JEDDAH
TEHRAN
DUBAI
KABUL
KARACHI
DELHI
DHAKA
YANGON
BANGKOK
HONG KONG
SEOUL
TOKYO
ADELAIDE
SYDNEY
NOUMEA
WELLINGTON
City
City
GMT
Other major cities in same time zone
Code
Differential
City Code Table
– – –
HNL
ANC
LAX
DEN
CHI
NYC
CCS
RIO
– – –
– – –
GMT
LON
PAR
BER
ATH
CAI
JRS
JED
THR
DXB
KBL
KHI
DEL
DAC
RGN
BKK
HKG
SEL
TYO
ADL
SYD
NOU
WLG
–11
–10
–9
–8
–7
–6
–5
–4
–3
–2
–1
+0
+1
+2
+3
+3.5
+4
+4.5
+5
+5.5
+6
+6.5
+7
+8
+9
+9.5
+10
+11
+12
PAGO PAGO
PAPEETE
NOME
SAN FRANCISCO, LAS VEGAS, VANCOUVER,
SEATTLE, DAWSON CITY, TIJUANA
EL PASO, EDMONTON, CULIACAN
HOUSTON, DALLAS/FORT WORTH,
NEW ORLEANS, MEXICO CITY, WINNIPEG
MONTREAL, DETROIT, MIAMI, BOSTON,
PANAMA CITY, HAVANA, LIMA, BOGOTA
LA PAZ, SANTIAGO, PORT OF SPAIN
SAO PAULO, BUENOS AIRES, BRASILIA,
MONTEVIDEO
PRAIA
DUBLIN, LISBON, CASABLANCA, DAKAR,
ABIDJAN
MILAN, ROME, MADRID, AMSTERDAM, ALGIERS,
HAMBURG, FRANKFURT, VIENNA, STOCKHOLM
HELSINKI, ISTANBUL, BEIRUT, DAMASCUS,
CAPE TOWN
KUWAIT, RIYADH, ADEN, ADDIS ABABA, NAIROBI,
MOSCOW
SHIRAZ
ABU DHABI, MUSCAT
MALE
MUMBAI, KOLKATA
COLOMBO
JAKARTA, PHNOM PENH, HANOI, VIENTIANE
SINGAPORE, KUALA LUMPUR, BEIJING, TAIPEI,
MANILA, PERTH, ULAANBAATAR
PYONGYANG
DARWIN
MELBOURNE, GUAM, RABAUL
PORT VILA
CHRISTCHURCH, NADI, NAURU ISLAND
• Based on data as of December 2002.