MA2310-ED © 2021 CASIO COMPUTER CO., LTD.

Watch Operation Guide 5660

Contents Alarm Temperature Measurement

Configuring Alarm Settings Checking the Current Temperature

Precautions Configuring the Hourly Time Signal Setting Calibrating Temperature Readings (Offset)

Operating Precautions Turning Off an Alarm or the Hourly Time Signal Specifying the Temperature Measurement
Unit
User Maintenance
Temperature Reading Precautions
Battery Digital Compass

Taking a Compass Reading

Viewing Altitude Records
Before Getting Started... Calibrating Compass Readings
Viewing Recorded Data
General Guide Calibrating Compass Readings
Setting Up for True North Readings Deleting Data
Watch Face and Display Indicators (Magnetic Declination Calibration)

Navigating Between Modes Digital Compass Reading Precautions

Stopwatch
Mode Overview

Using the Crown Altitude Measurement Measuring Elapsed Time

Shifting the Hands Measuring a Split Time

Checking the Current Altitude

Charging Timing the First and Second Place Finishers

Calibrating Altitude Readings (Offset)

Viewing the Face in the Dark Checking the Altitude Differential from a
Reference Point Timer
Setting the Auto Measurement Interval
Time Adjustment Setting a Start Time
Recording Altitude Readings
Time Adjustment Using a Time Signal Using the Timer
Specifying the Altitude Measurement Unit
Overview
Appropriate Signal Reception Location Altitude Reading Precautions
Hand Alignment Adjustment
Time Signal Reception Ranges
Auto Time Calibration Signal Receive Adjusting Hand Alignment
Enabling and disabling Auto Receive
Barometric Pressure
Measurement
Manual Time Calibration Signal Receive
Receive Level Indicator
Checking the Current Barometric Pressure
Other Settings
Checking the Last Time Adjustment
Result Checking Changes in Barometric Pressure Enabling the Button Operation Tone
Signal Reception Precautions Over Time
Configuring Power Saving Function Settings
Using Watch Operations to Adjust the Time Checking the Change in Barometric Pressure
Setting between Two Readings

Sudden Barometric Pressure Change Other Information

Indications
World Time City Table
Calibrating Barometric Pressure Readings
Checking World Time (Offset) Specifications

Specifying a World Time City Specifying the Barometric Pressure Unit

Swapping Your Home Time and World Time Barometric Pressure Reading Precautions Troubleshooting

OPUM-F 1
 Watch Operation Guide 5660
Do not use your watch for scuba diving or The inside surface of the watch glass may
Precautions
● ●

other types of diving that requires air tanks. fog when the watch is exposed to a sudden
● Watches that do not have WATER RESIST drop in temperature. No problem is
or WATER RESISTANT marked on the indicated if the fogging clears up relatively
back cover are not protected against the quickly. Sudden and extreme temperature
Operating Precautions changes (such as coming into an air
effects of sweat. Avoid using such a watch
under conditions where it will be exposed to conditioned room in the summer and
● Water Resistance
large amounts of sweat or moisture, or to standing close to an air conditioner outlet,
● The information below applies to watches or leaving a heated room in the winter and
direct splashing with water.
with WATER RESIST or WATER allowing your watch to come into contact
RESISTANT marked on the back cover.
● Even if a watch is water resistant, note the
with snow) can cause it to take longer for
usage precautions described below. Such
Water Resistance Under Daily Use glass fogging to clear up. If glass fogging
types of use reduce water resistance
does not clear up or if you notice moisture
Marking on watch front or on No BAR performance and can cause fogging of the
inside of the glass, immediately stop using
back cover mark glass.
ー Do not operate the crown or buttons while
your watch and take it to your original
Example of Daily Use retailer or to an authorized CASIO service
your watch is submersed in water or wet.
center.
Hand washing, rain Yes ー Avoid wearing your watch while in the

Water-related work, swimming No bath.

● Your water-resistant watch has been tested
ー Do not wear your watch while in a heated in accordance with International
Windsurfing No
swimming pool, sauna, or any other high Organization for Standardization
Skin diving No
temperature/high humidity environment. regulations.
Enhanced Water Resistance Under Daily ー Do not wear your watch while washing
● Band
Use your hands or face, while doing
5 Atmospheres ● Tightening the band too tightly can cause
housework, or while performing any other
you to sweat and make it difficult for air to
Marking on watch front or on task that involves soaps or detergents.
5BAR pass under the band, which can lead to skin
back cover ● After submersion in seawater, use plain
irritation. Do not fasten the band too tightly.
Example of Daily Use water to rinse all salt and dirt from your
There should be enough room between the
watch.
Hand washing, rain Yes band and your wrist so you can insert your
● To maintain water resistance, have the finger.
Water-related work, swimming Yes
gaskets of your watch replaced periodically
Windsurfing No
● Deterioration, rust, and other conditions can
(about once every two or three years).
Skin diving No cause the band to break or come off of your
● A trained technician will inspect your watch watch, which in turn can cause band pins to
10 Atmospheres for proper water resistance whenever you fly out of position or to fall out. This creates
have its battery replaced. Battery the risk of your watch falling from your wrist
Marking on watch front or on
10BAR replacement requires the use of special and becoming lost, and also creates the risk
back cover
tools. Always request battery replacement of personal injury. Always take good care of
Example of Daily Use from your original retailer or from an your band and keep it clean.
Hand washing, rain Yes authorized CASIO service center. ● Immediately stop using a band if you even
Water-related work, swimming Yes ● Some water-resistant watches come with notice any of the following: loss of band
Windsurfing Yes fashionable leather bands. Avoid flexibility, band cracks, band discoloration,
Skin diving Yes swimming, washing, or any other activity band looseness, band connecting pin flying
that causes direct exposure of a leather or falling out, or any other abnormality. Take
20 Atmospheres band to water. your watch to your original retailer or to a
Marking on watch front or on CASIO service center for inspection and
20BAR
back cover repair (for which you will be charged) or to
have the band replaced (for which you will
Example of Daily Use
be charged).
Hand washing, rain Yes
Water-related work, swimming Yes
Windsurfing Yes
Skin diving Yes

2
 Watch Operation Guide 5660
● Temperature ● Chemicals ● Leather Band
● Never leave your watch on the dashboard ● Do not allow your watch to come into ● Allowing your watch to remain in contact
of a car, near a heater, or in any other contact with thinner, gasoline, solvents, with other items or storing it together with
location that is subject to very high oils, or fats, or with any cleaners, adhesives, other items for long periods while it is wet
temperatures. Do not leave your watch paints, medicines, or cosmetics that contain can cause the color of the leather band to
where it will be exposed to very low such ingredients. Doing so can cause transfer to the other items or the color of the
temperatures. Temperature extremes can discoloration of or damage to the resin other items to transfer to the leather band.
cause your watch to lose or gain time, to case, resin band, leather, and other parts. Be sure to dry off your watch thoroughly with
stop, or otherwise malfunction. a soft cloth before storing it and make sure
● Storage
● Leaving your watch in an area hotter than it is not in contact with other items.
● If you do not plan to use your watch for a
+60 °C (140 °F) for long periods can lead to ● Leaving a leather band where it is exposed
long time, thoroughly wipe it free of all dirt,
problems with its LCD. The LCD may to direct sunlight (ultraviolet rays) for long
sweat, and moisture, and store it in a cool,
become difficult to read at temperatures periods or failure to clean dirt from a leather
dry place.
lower than 0 °C (32 °F) and greater than band for long periods can cause it to
+40 °C (104 °F). ● Resin Components become discolored.

● Impact ● Allowing your watch to remain in contact CAUTION:

with other items or storing it together with Exposing a leather band to rubbing or dirt
● Your watch is designed to withstand impact
other items for long periods while it is wet can cause color transfer and discoloration.
incurred during normal daily use and during
can cause color on resin components to
light activity such as playing catch, tennis, ● Metal Components
transfer to the other items, or the color of the
etc. Dropping your watch or otherwise ● Failure to clean dirt from metal components
other items to transfer to the resin
subjecting it to strong impact, however, can can lead to formation of rust, even if
components of your watch. Be sure to dry
lead to malfunction. Note that watches with components are stainless steel or plated. If
off your watch thoroughly before storing it
shock-resistant designs (G‑SHOCK, metal components exposed to sweat or
and make sure it is not in contact with other
BABY‑G, G‑MS) can be worn while water, wipe thoroughly with a soft,
items.
operating a chain saw or engaging in other absorbent cloth and then place the watch in
activities that generate strong vibration, or ● Leaving your watch where it is exposed to
a well-ventilated location to dry.
while engaging in strenuous sports direct sunlight (ultraviolet rays) for long
● Use a soft toothbrush or similar tool to scrub
activities (motocross, etc.) periods or failure to clean dirt from your
the metal with a weak solution of water and
watch for long periods can cause it to
● Magnetism a mild neutral detergent, or with soapy
become discolored.
water. Next, rinse with water to remove all
● The hands of analog and combination ● Friction caused by certain conditions
remaining detergent and then wipe dry with
(analog-digital) watches are moved by a (strong external force, sustained rubbing,
a soft absorbent cloth. When washing metal
motor that uses magnetic force. When such impact, etc.) can cause discoloration of
components, wrap the watch case with
a watch is close to a device (audio painted components.
kitchen plastic wrap so it does not come into
speakers, magnetic necklace, cell phone, ● If there are printed figures on the band, contact with the detergent or soap.
etc.) that emits strong magnetism, the
strong rubbing of the printed area can cause
magnetism can cause timekeeping to slow
discoloration.
down, speed up, or stop, resulting in the
incorrect time being displayed.
● Leaving your watch wet for long periods can
cause fluorescent color to fade. Wipe the
● Timekeeping accuracy may be affected if
watch dry as soon as possible after it
the watch itself becomes magnetized. Also,
becomes wet.
very strong magnetism (from medical
equipment, etc.) should be avoided
● Semi-transparent resin parts can become
because it can cause malfunction of your discolored due to sweat and dirt, and if
watch and damage to electronic exposed to high temperatures and humidity
components. for long periods.
● Daily use and long-term storage of your
● Electrostatic Charge
watch can lead to deterioration, breaking, or
● Exposure to very strong electrostatic bending of resin components. The extent of
charge can cause your watch to display the such damage depends on usage conditions
wrong time. Very strong electrostatic and storage conditions.
charge even can damage electronic
components.
● Electrostatic charge can cause the display
to go blank momentarily or cause a rainbow
effect on the display.

3
 Watch Operation Guide 5660
● Bacteria and Odor Resistant Band ● Dangers of Poor Watch Care
User Maintenance
● The bacteria and odor resistant band Rust
protects against odor generated by the ● Caring for Your Watch
● Though the metal steel used for your watch
formation of bacteria from sweat, which Remember that you wear your watch next to is highly rust-resistant, rust can form if your
ensures comfort and hygiene. In order to your skin, just like a piece of clothing. To watch is not cleaned after it becomes dirty.
ensure maximum bacteria and odor ensure your watch performs at the level for ー Dirt on your watch can make it impossible
resistance, keep the band clean. Use an which it is designed, keep it clean by for oxygen to come into contact with the
absorbent soft cloth to thoroughly wipe the frequently wiping with a soft cloth to keep your metal, which can lead to breakdown of
band clean of dirt, sweat, and moisture. A watch and band free of dirt, sweat, water and the oxidization layer on the metal surface
bacteria and odor resistant band other foreign matter. and the formation of rust.
suppresses the formation of organisms and ● Whenever your watch is exposed to sea Rust can cause sharp areas on metal
bacteria. It does not protect against rash
●

water or mud, rinse it off with clean fresh components and can cause band pins to fly
due to allergic reaction, etc.
water. out of position or to fall out. If you ever notice
● Liquid Crystal Display ● For a metal band or a resin band with metal any abnormality immediately stop using
● Display figures may be difficult to read when parts, use a soft toothbrush or similar tool to your watch and take it to your original
viewed from an angle. scrub the band with a weak solution of water retailer or to an authorized CASIO service
and a mild neutral detergent, or with soapy center.
● Watch with Data Memory water. Next, rinse with water to remove all ● Even if the surface of the metal appears
● Allowing the battery to go dead, replacing remaining detergent and then wipe dry with clean, sweat and rust in crevasses can soil
the battery, or having your watch repaired a soft absorbent cloth. When washing the the sleeves of clothing, cause skin irritation,
can cause all data in watch memory to be band, wrap the watch case with kitchen and even interfere with watch performance.
lost. Note that CASIO Computer Co., Ltd. plastic wrap so it does not come into contact
assumes no responsibility for any damages with the detergent or soap. Premature Wear
or losses caused by data lost due to ● For a resin band, wash with water and then
● Leaving sweat or water on a resin band or
malfunction or repair of your watch, wipe dry with a soft cloth. Note that bezel, or storing your watch an area subject
replacement of the battery, etc. Be sure to sometimes a smudge like pattern may to high moisture can lead to premature
keep separate written copies of all appear on the surface of a resin band. This wear, cuts, and breaks.
important data. will not have any effect on your skin or Skin Irritation
clothing. Wipe with a cloth to remove the
● Watch Sensors ● Individuals with sensitive skin or in poor
smudge pattern.
● A watch sensor is a precision instrument. physical condition may experience skin
● Clean water and sweat from a leather band irritation when wearing a watch. Such
Never try to take it apart. Never try to insert
by wiping with a soft cloth. individuals should keep their leather band
any objects into the openings of a sensor,
and take care to ensure that dirt, dust, or ● Not operating a watch crown, buttons, or or resin band particularly clean. Should you
other foreign matter does not get into it. rotary bezel could lead to later problems ever experience a rash or other skin
After using your watch where it has been with their operation. Periodically rotate the irritation, immediately remove your watch
immersed in saltwater, rinse it thoroughly crown and rotary bezel, and press buttons and contact a skin care professional.
with fresh water. to maintain proper operation.

Note that CASIO Computer Co., Ltd. Battery

assumes no responsibility for any
damage or loss suffered by you or any ● The special rechargeable battery used by
third party arising through the use of your your watch is not intended to be removed or
watch or its malfunction. replaced by you. Use of a rechargeable
battery other than the special one specified
for your watch can damage your watch.
● The rechargeable (secondary) battery is
charged when the solar panel is exposed to
light, so it does not require regular
replacement as the primary battery
requires. Note, however, that long use or
operating conditions can cause the
capacity or charging efficiency of the
rechargeable battery to deteriorate. If you
feel that the amount of operation provided
by charging is too short, contact your
original retailer or CASIO service center.

4
 Watch Operation Guide 5660
Before Getting Important! General Guide
Started... ● This watch is not a special-purpose ① ② ③ ④
measuring instrument. Measurement
This section provides an overview of the watch function readings are intended for
and introduces convenient ways it can be general reference only.
used. ● Whenever using the Digital Compass ⑦
of this watch for serious trekking,
● Watch Features
mountain climbing, or other activities,
● Solar Charging be sure to always take along another
Sunlight and artificial light generate compass to confirm readings. If the
electricity for watch operation as it charges. readings produced by the Digital ⑤ ⑥
Compass of this watch are different
● Time Signal Reception
from those of the other compass, A Mode hand
The watch receives a radio signal
perform 2-point calibration of the B Hour hand
containing time information and uses it to
Digital Compass to ensure better C Second hand
keep its time setting accurate.
accuracy. D Minute hand
● World Time ー Compass readings and calibration
E Day of the week
You can display the current time in any one will not be possible if the watch is in
F Month, day
of 29 cities around the globe, as well as for the vicinity of a permanent magnet
G Crown
UTC (Coordinated Universal Time). (magnetic accessory, etc.), metal
objects, high-voltage wires, aerial A button
● Alarm
wires, or electrical household
An alarm sounds whenever a time specified Pressing this button in the Timekeeping Mode
appliances (TV, computer,
by you is reached. enters the Altimeter Mode.
cellphone, etc.)
● Digital Compass l Digital Compass B button
You can use the Compass Mode to ● The watch’s altimeter function Each press cycles between watch modes.
determine the direction of north, and to calculates and displays relative In any mode, hold down this button for at least
check your bearing to a destination. altitude based on barometric pressure two seconds to return to the Timekeeping
● Altitude Measurement readings produced by its pressure Mode.
sensor. Because of this, altitude
You can use this function to take an altitude
values displayed by the watch may be C button
reading at your current location.
different from your actual elevation Pressing this button in the Timekeeping Mode
You can record the altitude, along with the
and/or sea level elevation indicated for enters the Compass Mode.
date and time of the measurement.
the area where you are located.
You can also measure the altitude D button
Regular calibration in accordance with
differential between two points.
the local altitude (elevation) Pressing this button in the Timekeeping Mode
● Barometric Pressure Measurement cycles between displays.
indications is recommended.
You can display the current barometric l Altitude Measurement L button
pressure tendency, which helps you be on
the alert for noteworthy pressure changes. Press to turn on illumination.
● Temperature Measurement Note
The watch can be used to take current air
temperature readings. ● The illustrations included in this
● Viewing Altitude Records operation guide have been created to
facilitate explanation. An illustration
You can view or delete records of altitude
may differ somewhat from the item it
measurements.
represents.
● Stopwatch
You can use the stopwatch to measure up
to 24 hours of elapsed time in units of 1/100
of a second.
● Timer
Countdown from a start time specified by
you. An alarm sounds when the countdown
reaches zero.

5
 Watch Operation Guide 5660
Watch Face and Display I During 12-hour timekeeping, the second Navigating Between Modes
Indicators hand points to [A] for a.m. times and [P] for
Your watch has the modes shown below.
p.m. times
● To return to the Timekeeping Mode from
J The second hand indicates altitude/ any other mode, hold down (B) for at least
① ⑦
barometric pressure differential. two seconds.
② ⑧
③
K Displayed when an alarm is turned on. Compass Mode Altimeter Mode
A
④ ⑤⑥
L Appears when the hourly time signal is on.
⑨ C

M Displayed when the indicated time is Timekeeping Mode

summer time.

N Displayed while barometric pressure C B A B

⑩ change indication is enabled.

O Shows the barometric pressure

measurement unit.

B B
⑪ ⑫ ⑬ ⑭ ⑮

Receive Mode Barometer Mode

A In the Barometer Mode, the mode hand

points to [BARO].
B B
B In the Thermometer Mode, the mode hand
points to [TEMP]. World Time Mode Thermometer Mode

C In the Altitude Record Recall Mode, the

mode hand points to [REC].

D In the Stopwatch Mode, the mode hand

points to [ST].

E In the Timer Mode, the mode hand points B B

to [TR].
Alarm Mode Altitude Record Recall
Mode
F In the Alarm Mode, the mode hand points
to [AL].

G In the Receive Mode, the mode hand

points to [R/C].

H In the World Time Mode, the mode hand

points to [WT]. B B

Timer Mode Stopwatch Mode

Use the buttons in the illustration above to

navigate between modes.

6
 Watch Operation Guide 5660
● Compass Mode ● Altitude Record Recall Mode
Mode Overview
Use this mode to take direction and bearing Use this mode to view altitude records.
● Timekeeping Mode angle readings. l Viewing Altitude Records
In this mode, the digital display shows the l Digital Compass
①
current day of the week, month, and day. Data search

You can also use (D) to scroll display contents

through the items below. Objective

● Barometric pressure graph, month, day ①

● Hour, minute, second
Data search
Day of the week, month, day

A Number of the record displayed last time

Remeasure the Altitude Record Recall Mode was
used
② ③
● Stopwatch Mode

A North indication Use this mode to measure elapsed time.

D D l Stopwatch
B Bearing at 12 o’clock
① ② ③ Split/reset
Hour, minute, second
Barometric pressure
graph, month, day
C Bearing angle at 12 o’clock
● Barometer Mode ④

Use this mode to take barometric pressure

Barometric pressure graph readings at your current location.
l Barometric Pressure Measurement Start/Stop

Display screen ①
D navigation
A Stopwatch hours
● Altimeter Mode
B Stopwatch minutes
Use this mode to take an altitude reading for
your current location. C Stopwatch seconds
l Altitude Measurement Remeasure

Display screen ① ② ③
D Stopwatch: 1/100 second
navigation
● Timer Mode
A Barometric pressure differential/current Use this mode to countdown from a desired
time seconds start time.
l Timer
B Barometric pressure graph
Remeasure
① ②
C Barometric pressure Reset
② ③
● Thermometer Mode
A Altitude differential/current time seconds Use this mode to take temperature readings
at your current location.
B Altitude graph
l Temperature Measurement Start/Stop

C Altitude ①

A Timer minutes

B Timer seconds

Remeasure

A Temperature

7
 Watch Operation Guide 5660
● Alarm Mode
Using the Crown Shifting the Hands
The watch will beep when an alarm time is
reached. The watch’s crown is a screw-in (screw lock) Hand shift moves the hands out of the way for
l Alarm type. To use the crown, you first need to rotate easy viewing of display information.
it towards you (leftwards) to loosen it.
① ②
Crown 1. While holding down (L), press (B).
This will shift the analog hands to allow
Select alarm/
easy viewing of display information.
On/off hourly time signal

②
③
Loosen

Select alarm/ Important!

hourly time signal
● To prevent loss of water resistance
A Alarm number and/or damage due to impact, be sure 2. To return the hands to their normal
to screw the crown in by rotating it timekeeping positions, press (A), (B), (C),
B Alarm or hourly time signal status (on/off) away from you as you push it in. or (D).
Screw in
C Alarm hour/minute Note

● World Time Mode

● If you leave the watch with its hands
You can view the current time in 29 cities and shifted and do not perform any
UTC (Coordinated Universal Time) time. operation for about ten seconds, the
l World Time hands resume normal timekeeping
①
● When pushing the crown back in, take automatically.
Show current city care not to apply too much force.

②
● Fast Forward/Fast Reverse
After pulling out the crown, rotating it quickly
in succession in either direction will start a fast
forward or fast reverse operation. While a fast
③ forward operation is in progress, quickly
rotating the crown in succession again will
increase the speed even further.
A City Codes (World Time Codes)
● Stopping Fast Forward/Fast Reverse
B World Time City current time Rotate the crown in the direction opposite that
of the ongoing operation or press any button.
C Home City time
● Receive Mode
Note

With this mode, you can receive a time signal ● If you do not perform any operation for
manually. about two minutes after pulling out the
l Time Adjustment Using a Time Signal crown, crown operations will
automatically become disabled. If that
happens, push the crown back in and
①
then pull it out again.

A Receive level indicator

8
 Watch Operation Guide 5660
● Checking the Charge Level Charge Level 4: Low
Charging
A display indicator shows the watch’s charge Battery charge is lower than Level 3, and all
This watch runs on power supplied from a level when you enter the Timekeeping Mode. functions are disabled. Also, all hands are
stopped.
rechargeable (secondary) battery that is
charged by a solar panel. The solar panel is
integrated into the face of the watch, and
power is generated whenever the face is
exposed to light.

● Charging the Watch

When you are not wearing the watch, put it in

● The display will show charge levels 4 and 5,
a location where it is exposed to bright light.
even if the watch is not in the Timekeeping Charge Level 5: Dead
Mode.
All hands are stopped and digital displays are
Charge Level 1: Good blank. Memory data is lost, and watch settings
All functions enabled. are returned to their initial factory defaults.

Important!

● Should the battery go low or go dead,

expose the face (solar panel) to light as
While you are wearing the watch, make sure
Charge Level 2: Good soon as possible.
that its face (solar panel) is not blocked from
All functions enabled.
light by the sleeve of your clothing. Power
generation efficiency is reduced even when
the face of the watch is blocked only partially. Note

YES NO
● If [RECOVER] is flashing on the
display, it means that all functions are
Charge Level 3: Low
disabled due to momentary battery
The functions below are disabled. Also, the power consumption.
second hand jumps at two-second intervals. ● Exposing the watch face to light after
● Time signal reception the battery goes dead causes the
● Compass, altitude, barometric pressure, [CHARGE] indicator to appear. This
temperature measurements indicates charging has started.
● Face illumination
Important!
● Sounds (alarms, etc.)
● Depending on light intensity and local
conditions, the watch may become hot
to the touch when exposed to light for
charging. Take care to avoid burn One second later
injury after charging. Also, avoid
charging the watch under high-
temperature conditions like the ones
described below.
ー On the dashboard of a vehicle

parked in the sun

ー Near an incandescent light bulb or

other source of heat

ー Under direct sunlight or in other hot

areas for long periods

● The display panel may become black
(or white, depending on the LCD type)
under very high temperatures. This is
temporary, and the display will return
to normal at lower temperatures.

9
 Watch Operation Guide 5660
● Charging Time Guidelines ● Power Saving Function
Viewing the Face in the Dark
The table below shows guidelines for Leaving the watch in a dark location for about
approximate charging times. one hour between the hours of 10 p.m. and 6 The face of the watch can be illuminated for
a.m. will cause the display to go blank, and the viewing in the dark.
Charging Times Required for 1 Day of
watch to enter Level 1 power saving. If the
Operation ● To illuminate the face manually
watch is left in this condition for six or seven
Approximate days, the watch will enter Level 2 power Pressing (L) turns on illumination.
Light Level (Lux)
Charging Time saving. ● Illumination turns off automatically if an
50,000 8 minutes alarm starts to sound or if you perform a
Power Saving Level 1 :
10,000 30 minutes crown operation.
The second hand stops at 12 o’clock and the
5,000 48 minutes ● Illumination does not turn on while a signal
digital display goes blank to save power.
500 8 hours receive operation or a hand movement
Power Saving Level 2 : operation is in progress. Also, illumination
Charge Recovery Times
All hands stop and the digital display goes may not turn on while a sensor is taking a
● Sunny day, outdoors (50,000 lux) blank to save power. All functions are reading.
disabled.
Dead battery n Medium
3 hours
charge Recovering from Power Saving Operation
Medium charge n High Use one of the operations below to exit power
22 hours
charge saving.
High charge n Full charge 6 hours ● Press any button.
● Move the watch to a bright location.
● Sunny day, near a window (10,000 lux) ● Trigger auto light by angling the watch ● To illuminate the face when Auto Light
towards your face.
Dead battery n Medium is enabled
7 hours
charge If Auto Light is enabled, face illumination will
Note
Medium charge n High turn on automatically whenever the watch is
83 hours
charge positioned at an angle of 40 degrees or more.
● The watch will not enter power saving
High charge n Full charge 23 hours in the cases below.
ー While in the Stopwatch Mode 40
degrees
● Overcast day, near a window (5,000 lux) ー While in the Timer Mode
or more
ー While the barometric pressure

Dead battery n Medium change indicator is displayed

10 hours
charge ● You can enable or disable Power
Medium charge n High Saving.
135 hours Important!
charge
l Configuring Power Saving
High charge n Full charge 36 hours Function Settings ● Auto Light may not operate properly
● Note that the watch also may enter when the watch is at a horizontal angle
● Indoor fluorescent lighting (500 lux) power saving if its face is blocked from of 15 degrees or greater from
light by your sleeve while you are horizontal as shown in the illustration
Dead battery n Medium wearing it. below.
119 hours
charge
Medium charge n High
-
charge
High charge n Full charge -

Note ● Electro-static charge or magnetism

can interfere with proper auto light
● Actual charging time depends on the operation. If this happens, try lowering
charging environment, watch settings, your arm and then angle it towards
and other factors. your face again.
● When moving the watch you may note
a slight rattling sound. This is due to
operation of the auto light switch,
which determines the current
orientation of the watch. It does not
indicate malfunction.

10
 Watch Operation Guide 5660
● Specifying the Illumination Duration
Note
You can select either 1.5 seconds or three
Time Adjustment
seconds as the illumination duration.
● Auto Light is disabled when any one of
the conditions below exists. Your watch can receive time calibration
1. Enter the Timekeeping Mode. signals and adjust its date and time setting.
ー Alarm, timer alert, or other beeper

l Navigating Between Modes

sounding
ー Hand movement operation is in
2. Pull out the crown.
progress This causes [CITY] to flash on the display
ー Watch in the Compass Mode
and the second hand to move to the
ー While a time signal receive
current Home City.
operation is in progress
Second hand

● Configuring the Auto Light Setting

You can enable or disable Auto Light as

required.

1. Enter the Timekeeping Mode.

l Navigating Between Modes
Crown
Time Adjustment Using a
2. Pull out the crown. Home City Time Signal
This causes [CITY] to flash on the display
3. Press (B) four times. Overview
and the second hand to move to the
current Home City. [LIGHT] appears on the display with [1] or The watch’s time and day settings can be
[3] flashing. configured in accordance with a received time
Second hand
4. Rotate the crown to select an illumination calibration signal.
duration.
Important!
[1]: 1.5-second illumination
[3]: 3-second illumination ● In order to make it possible for the
current time setting to be adjusted
Crown correctly based on time calibration
signal reception, you need to specify
Home City
the area where you are using the
watch.
3. Press (B) three times. l Setting a Home City
[ ] appears on the display with
[ON] or [OFF] flashing.
5. Push the crown back in to complete the Note
setting operation.
● Areas where time signal reception is
Note supported are limited. When you are
using the watch in an area where time
● If you do not perform any operation for calibration signal reception is not
about two minutes after pulling out the possible, adjust time and day settings
crown, crown operations will manually.
automatically become disabled. If that l Using Watch Operations to Adjust
happens, push the crown back in and the Time Setting
4. Rotate the crown to enable or disable the
then pull it out again.
Auto Light.

5. Push the crown back in to complete the

setting operation.

Note

● If you do not perform any operation for

about two minutes after pulling out the
crown, crown operations will
automatically become disabled. If that
happens, push the crown back in and
then pull it out again.

11
 Watch Operation Guide 5660
Appropriate Signal Reception Time Signal Reception Ranges Auto Time Calibration Signal
Location ● Japan (JJY)
Receive
A time calibration signal can be received while The Japan time signal radio stations are An automatic time calibration signal receive
the watch is near a window. located on Mt. Otakadoya in Fukushima and operation is performed and the time and day
● Position the watch so its 12 o’clock side is Mt. Hagane in Fukuoka/Saga. settings are adjusted between midnight and
facing the window. The reception range of the Japanese time 5:00 a.m. Once a signal receive operation is
signals is approximately 1,000 km from each successful, no more auto receive operations
● Keep metal objects away from the watch.
transmission station. are performed that day.
● Do not move the watch.
● Do not perform any operation on the watch. ● China (BPC) 1. Place the watch near a window or some
The China time signal radio station is located other location appropriate for signal
reception.
12 o'clock
in Shangqiu, Henan Province, China.
The reception range of the Chinese time ● [RC !] is shown on the display while time
signal is approximately 1,500 km from the signal reception is in progress.
transmission station. ● When a receive operation is successful,
the watch adjusts its current time and
● United States (WWVB)
day settings automatically, and then
The United States time signal radio station is returns to the Timekeeping Mode.
located in Fort Collins, Colorado.
The reception range of the U.S. time signal is Note
approximately 3,000 km from the transmission
Note
station. ● Reception takes anywhere from about
● You may experience time calibration ● U.K. (MSF)/Germany (DCF77) two minutes to about 10 minutes. It can
signal reception problems in the areas take as long as 20 minutes.
The U.K. time signal radio station is located in
described below. Anthorn, Cumbria.
ー Among or near buildings
The German time signal radio station is
ー While riding in a vehicle
located in Mainflingen, southeast of Frankfurt. Enabling and disabling Auto
ー Near household appliances, office
The reception range of the U.K. and German Receive
machines, mobile phones, etc. time signals is approximately 1,500 km from
ー On a construction site, in an airport,
You can stop auto receive by disabling the
each transmission station. Auto Receive setting.
or any other location where radio
wave interference occurs
Note Note
ー Near high-voltage lines

ー In mountainous areas or behind a

● Even if you are within the normal While the Home City setting is one
mountain
●

reception range of a time calibration where time signal reception is

signal, reception may be made possible, you can enable or disable
impossible by the following factors: auto receive as required.
geographic contours, weather, the
l Time Signal Reception Ranges
season, the time of day, wireless
noise.
● A time calibration signal cannot be
1. Enter the Receive Mode.
received while the city selected as your
l Navigating Between Modes
Home City is one that does not support
signal reception. 2. Pull out the crown.
[AUTORC] appears on the display with
[ON] or [OFF] flashing.

Crown

3. Rotate the crown to enable or disable Auto

Receive.

4. Push the crown back in to complete the

setting operation.

12
 Watch Operation Guide 5660
Note Receive Level Indicator Signal Reception Precautions
While a receive operation is in progress, its ● When the watch is unable to adjust its time
● If you do not perform any operation for current status is indicated on the display as in accordance with a calibration signal for
about three minutes while performing shown below. Use the level indicator to find a some reason, average timekeeping
the Auto Receive on/off operation, the location where signal reception is stable. accuracy is within ±15 seconds per month.
watch automatically returns to the ● Note that an internal decoding process the
Timekeeping Mode.
watch performs after it receives a signal
● If you do not perform any operation for may cause the time setting to be slightly off
about two minutes after pulling out the (by less than one second).
crown, crown operations will ● Time calibration signal reception is not
automatically become disabled. If that
possible under the conditions described
happens, push the crown back in and
below.
Receive level indicator
then pull it out again. ー While battery power is low

ー In any mode besides the Timekeeping

Mode
Manual Time Calibration Signal Unstable Stable ー When the watch is at Level 2 power

Receive saving
ー While a compass reading, barometric

1. Place the watch near a window or some Note pressure measurement, temperature
other location appropriate for time signal measurement, or altitude measurement
reception. ● It takes about 10 seconds for time operation is in progress
ー While the barometric pressure change
2. Enter the Receive Mode. signal reception conditions to stabilize.
indication is enabled
l Navigating Between Modes
● Reception conditions are affected by
ー While a timer countdown operation is in
weather, the time of day, the
3. Hold down (A) for at least two seconds surrounding environment, etc.
progress
ー While the Home City area setting is one
until [RC !] appears on the display.
This indicates that the receive operation where time signal reception is not
has started. After the receive operation is possible
Checking the Last Time Adjustment ー While the watch is outside the time signal
complete, the watch’s time and day
Result reception range
settings will be adjusted accordingly.
● When the receive operation is successful,
1. Enter the Receive Mode.
the time and/or day settings will be adjusted
l Navigating Between Modes
automatically. Summer time will not be
This displays the date and time of the last applied correctly in the case described
successful receive operation. below.
ー When the summer time start date and
Last receive time
Receive level indicator time, end date and time, or other rules are
changed by authorities
● The level indicator shows the signal ● As of January 2021, China does not
level ([L1], [L2], [L3]) while a receive observe summer time. If China starts to
operation is in progress. observe summer time in the future, the time
l Receive Level Indicator displayed by the watch for China may not be
correct.
Note
Last receive date
● The receive operation takes anywhere
from about two minutes to about 10
minutes. It can take as long as 20
minutes.
● Time calibration signal reception is
better at night than during the day.

13
 Watch Operation Guide 5660
● Setting the Time/Date
Using Watch Operations to 5. Rotate the crown to select a summer time
You can use the procedure below to adjust the
Adjust the Time Setting setting.
time and date settings when using the watch
Rotating the crown cycles through the where signal reception is not possible.
If, for some reason, you cannot use time signal
setting items shown below.
reception to adjust the current time setting,
you can adjust date, time, and Home City ● [AUTO] Important!
settings manually using watch button The watch switches between standard
operations. time and summer time automatically. ● If you are using the watch in an area
● [OFF] where signal receive operations are
● Setting a Home City possible, time and date settings using
The watch always indicates standard
Use the procedure in this section to select a time. the time signal is recommended.
city to use as your Home City. If you are in an Configure the Home City setting before
[ON]
●
●
area that observes summer time, you can also changing the current time and date
The watch always indicates summer
enable or disable summer time. settings.
time.
l Setting a Home City
1. Enter the Timekeeping Mode.
l Navigating Between Modes

2. Pull out the crown. 1. Enter the Timekeeping Mode.

This causes [CITY] to flash on the display l Navigating Between Modes
and the second hand to move to the
2. Pull out the crown.
current Home City.
6. Push the crown back in to complete the This causes [CITY] to flash on the display
Second hand setting operation. and the second hand to move to the
current Home City.
Note
Second hand
● If you do not perform any operation for
about two minutes after pulling out the
crown, crown operations will
Crown
automatically become disabled. If that
Home City happens, push the crown back in and
then pull it out again. Crown
3. Rotate the crown to move the second ● The [AUTO] summer time setting is
hand to the city code of the city you want valid when the watch’s Home City is in Home City

to set as your Home City. an area where a time signal can be

received. 3. Press (D).
● For information about city codes, refer
to the information below. This causes [HOUR-MIN] to flash on the
l City Table display.
● You can see if a time is a.m. ([A]) or p.m.
4. Press (B).
([P]) by checking the second hand
position.

4. Rotate the crown to change the minute

setting.

14
 Watch Operation Guide 5660
● Switching between 12-hour and 24-
5. Press (B). hour Timekeeping World Time
This causes [HOUR] to flash on the You can specify either 12-hour format or 24-
display. hour format for the time display. You can view the current time in 29 cities and
6. Rotate the crown to change the hour UTC (Coordinated Universal Time) time.
1. Enter the Timekeeping Mode.
setting.
l Navigating Between Modes
7. Press (B).
2. Pull out the crown.
This causes the current year setting to
This causes [CITY] to flash on the display
flash on the display.
and the second hand to move to the
8. Rotate the crown to change the year current Home City.
setting. Second hand

Crown Checking World Time

Year Crown

Home City 1. Enter the World Time Mode.

9. Press (B).
l Navigating Between Modes
This causes the month and day to flash on 3. Press (B) five times. This displays [WT] for about one second.
the display.
This causes [12H] or [24H] to flash on the Next, the hour and minute hands indicate
10. Rotate the crown to change the month and display. the current time in your World Time City.
day setting. At this time the second hand points to the
city code of your World Time City.
● The digital display shows the current
time in your Home City.
● To check whether the current time in
your World Time City is a.m. or p.m.,
Crown
press (A). This will cause the second
Month, day 4. Rotate the crown to select [12H] (12-hour hand to move to [A] (a.m.) or [P] (p.m.).
timekeeping) or [24H] (24-hour After three seconds, the second hand
11. On a time signal at the top of a minute, timekeeping). goes back to indicating the seconds.
push the crown back in to complete the ● To cause the second hand to move to
setting operation. the currently selected city, press (D).
After three seconds, the second hand
Note goes back to indicating the seconds.

City Codes (World Time Codes)

● If you do not perform any operation for
about two minutes after pulling out the World Time
crown, crown operations will Crown
automatically become disabled. If that
happens, push the crown back in and 5. Push the crown back in to complete the
then pull it out again. setting operation.

Note

● If you do not perform any operation for Home Time

about two minutes after pulling out the
crown, crown operations will
automatically become disabled. If that
happens, push the crown back in and
then pull it out again.

15
 Watch Operation Guide 5660
Specifying a World Time City Note Alarm
Use the procedure in this section to select a ● If you do not perform any operation for
World Time city. If you are in an area that The watch will beep when an alarm time is
about two minutes after pulling out the
observes summer time, you can also enable reached. You can set up to five different
crown, crown operations will
or disable summer time. alarms. The hourly time signal causes the
automatically become disabled. If that
happens, push the crown back in and watch to beep every hour on the hour.
1. Enter the World Time Mode.
then pull it out again. ● The beeper will not sound if battery power
l Navigating Between Modes is low.
● While [UTC] is selected as the city, you
2. Pull out the crown. will not be able to change or check the
This causes [CITY] to flash on the display summer time setting.
and the second hand to move to the
current Home City.
● Specifying UTC (Coordinated Universal
Second hand Time) as Your World Time City
To set UTC (Coordinated Universal Time) as
your World Time City, enter the World Time
Mode and then hold down (A) for at least three
seconds.

Crown

Home City Configuring Alarm Settings

3. Rotate the crown to move the second 1. Enter the Alarm Mode.
hand to the city code of the city you want
l Navigating Between Modes
to specify as your World Time City.
2. Use (A) and (C) to display the number
This displays the current time in the city
([AL1] to [AL5]) of the alarm whose
you select.
Swapping Your Home Time settings you want to change.
4. Press (B).
and World Time Alarm number
This causes [ON] or [OFF] to flash on the
display. In the World Time mode, hold down (D) for at
least three seconds until [ ] flashes,
and your Home City time swaps places with
your World Time.

Before swapping After swapping

Alarm time
5. Rotate the crown to select a summer time Home Time World Time

setting. 3. Pull out the crown.

● [OFF] This causes the hours and minutes digits
The watch always indicates standard to flash.
time.
Hours
● [ON] Minutes
The watch always indicates summer
time. World Time Home Time

6. Push the crown back in to complete the

setting operation.
Crown

4. Rotate the crown to change the minute

setting.
● The hour digit changes in sync with the
minute digit change.

16
 Watch Operation Guide 5660
5. Press (B). Configuring the Hourly Time 1. Enter the Alarm Mode.
This causes the hours digits to flash.
Signal Setting l Navigating Between Modes

Hours 2. Use (A) and (C) to scroll through alarm

1. Enter the Alarm Mode. numbers ([AL1] to [AL5]) and the hourly
l Navigating Between Modes time signal ([SIG]) screens until the one
2. Press (A) or (C) to display the hourly time whose setting you want to change is
signal screen ([SIG]). displayed.

Alarm number or hourly time signal

6. Rotate the crown to change the hour

setting.
● If you are using 12-hour timekeeping,
the time setting is indicated as [A] (a.m.)
or [P] (p.m.). 3. Press (D) to toggle the hourly time signal
between enabled and disabled.
● [SIG] (hourly time signal) is shown on
the display while the hourly time signal 3. Press (D) to turn off the displayed alarm or
is enabled. the hourly time signal.
● Each press of (D) toggles between ON
and OFF.
7. Push the crown back in to complete the ● Turning off all alarms causes [ALM]
setting operation. (alarm) to disappear from the display,
while disabling the hourly time signal
Note causes [SIG] (hourly time signal) to
disappear from the display.
● If you do not perform any operation for
about three minutes while in the Alarm Turning Off an Alarm or the
mode, the watch automatically returns Hourly Time Signal
to the Timekeeping Mode.
● If you do not perform any operation for To stop an alarm or the hourly time signal from
about two minutes after pulling out the sounding, perform the steps below to turn it
crown, crown operations will off.
automatically become disabled. If that ● To have an alarm or hourly time signal Note
happens, push the crown back in and sound again, turn it back on.
then pull it out again.
● If [ALM] (alarm) is still displayed, it
Note means that another alarm is still turned
on. To turn off all of the alarms, repeat
● To stop the alarm ● Indicators are displayed while any of steps 2 and 3 until the [ALM] (alarm)
To stop the alarm after it starts to sound when the alarms or the hourly time signal is indicator is no longer displayed.
an alarm time is reached, press any button. turned on.
● The applicable indicators are not
Note displayed while all of the alarms are
turned off and/or the hourly time signal
● A beeper sounds for 10 seconds when is turned off.
an alarm time is reached.
Alarm
Hourly time signal

17
 Watch Operation Guide 5660
Interpreting Bearing Readings ● Aligning a Map with Actual
Digital Compass Surroundings (Setting a Map)
Setting a map means to align the map so the
directions indicated on it are aligned with the
Objective
You can use the Compass Mode to determine
the direction of north, and to check your North
Bearing angle actual directions of your location. Once you
315°
bearing to a destination. 0°
set a map, you can more easily get a grasp of
the relationship between map markings and
actual geographic contours. To set a map with
this watch, align north on the map with the
north indication of the watch. Once you set the
map, you can compare your bearing on the
Bearing angle to objective map with your surroundings, which will help
Bearing to objective you determine your current location and
destination.
Directions: N (North), E (East), W (West), S ● Note that map reading skills and experience
(South) are required to determine your current
location and destination on a map.
Note
Important!
● Normally the compass indicates
● Check the information at the link below magnetic north. You can also Calibrating Compass
to find out how to ensure correct configure settings to indicate true Readings
readings. north.
l Calibrating Compass Readings l Setting Up for True North Calibrating Compass Readings
l Digital Compass Reading Readings (Magnetic Declination
Precautions Perform 2-point calibration whenever you
Calibration)
notice the watch’s compass readings are
l Magnetic North and True North
different from those of another compass, or
● After the initial reading is displayed, the before setting out on a climb or trek.
watch will continue to take readings
Taking a Compass Reading about every second for about the next
● Note that accurate compass readings
and/or calibration will not be possible in an
60 seconds. The watch will return to
area where strong magnetism is present.
1. Enter the Compass Mode. the Timekeeping Mode automatically
l Digital Compass Reading Precautions
l Navigating Between Modes about 60 seconds after you press (C).
● This operation can also be performed in ● Auto Light will not illuminate the face 2-Point Calibration
the Timekeeping Mode or Altimeter while a compass operation is in
Mode.
1. Enter the Compass Mode.
progress.
l Navigating Between Modes
2. Point 12 o’clock of the watch in the
● If an alarm or other beeper sounds, or
direction of your objective. if you turn on illumination by pressing 2. Pull out the crown.
(L) while a compass operation is in
This displays [o 1].
3. While keeping the watch horizontal, press progress, the compass operation will
(C). be suspended momentarily. The
This displays [COMP] and starts digital compass operation will resume when
compass readings. the beeper stops or illumination turns
off.
● The second hand points North. The
digital display shows one of 16 literal ● If you do not perform any operation for Crown
direction indications or the bearing about one minute while in the
angle. Compass Mode, the watch
automatically returns to the
● To retrigger the compass operation,
Timekeeping Mode.
press (C).

18
 Watch Operation Guide 5660
3. While keeping the watch horizontal, press Setting Up for True North Readings 4. Rotate the crown to select a magnetic
(C). (Magnetic Declination Calibration) declination direction and angle settings as
This starts calibration of the first point, If you want the watch to indicate true north desired.

which causes [o WAIT] to appear on the instead of magnetic north, you need to specify Setting range: 90° west to 90° east
display. When calibration is successful, your current location’s magnetic declination
[OFF]: Magnetic north
indicators appear on the display in the direction (east or west) and declination angle.
[E]: East declination (Magnetic north is
l Magnetic North and True North
following sequence: [OK] n [Turn 180°] east of true north.)
● The magnetic declination angle value can
n [p 2]. [W]: West declination (Magnetic north is
be set in 1° (degree) units only. Use a value
west of true north.)
4. Rotate the watch 180 degrees, taking care that is closest to the angle you want to set.
to be as exact as possible. Example: For an angle of 7.4°, set 7°. ● To return the setting to [OFF], press (A)
Example: For an angle of 7°40’ (7 degrees, and (C) at the same time.
40 minutes), set 8°. Magnetic declination direction

Note ＋

● Magnetic declination angles (east or −

west) and angle degree values for
specific locations can be found on
geographic maps, mountain climbing
Magnetic declination angle
5. Press (C).
maps, and other maps that include
● This starts calibration of the second
contour lines. 5. Push the crown back in to complete the
point, which causes [p WAIT] to appear setting operation.
on the display.
● When calibration is successful, [OK]
1. Enter the Compass Mode. Note
appears on the display and the watch
l Navigating Between Modes
returns to the Digital Compass screen. ● If you do not perform any operation for
2. Pull out the crown. about two minutes after pulling out the
6. Push the crown back in to complete the
crown, crown operations will
calibration operation. This displays [o 1].
automatically become disabled. If that
happens, push the crown back in and
Note
then pull it out again.
● If you do not perform any operation for
about two minutes after pulling out the ● Magnetic North and True North
crown, crown operations will Crown
There are actually two types of north:
automatically become disabled. If that
magnetic north and true north.
happens, push the crown back in and 3. Press (B).
then pull it out again. Magnetic north: North indicated by the needle
This displays [DEC] and the current
of a compass
● [ERR] will appear if calibration fails for magnetic declination setting.
some reason. If this happens, restart True north: Direction to the North Pole
the above procedure from step 2. As shown in the illustration below, magnetic
north and true north are not the same.

True north

Magnetic north

Earth

Note

● The north indicated on commercially

available maps is normally true north.

19
 Watch Operation Guide 5660
Digital Compass Reading Altitude Checking the Current
Precautions Altitude
Measurement
Location During Use
1. Enter the Altimeter Mode.
Taking readings near sources of strong The watch takes altitude readings and
l Navigating Between Modes
magnetism can cause reading error. Keep the displays results based on air pressure
Entering the Altimeter Mode will start
watch away from the following types of items. measurements taken by a built-in pressure
altitude measurement and display the
Permanent magnets (magnetic accessories, sensor.
altitude at your current location.
etc.), metal objects, high-voltage wires, aerial
wires, electrical household appliances (TVs, Altitude graph
computers, cellphones, etc.)
● Note that correct direction readings are not
possible indoors, especially inside of
reinforced concrete structures.
● Accurate direction readings are not
possible on electric trains, on boats, on
aircraft, etc.
Altitude
Storage Location
Exposure of the watch to magnetism can ● The watch takes altitude readings every
Important!
affect the accuracy of digital compass second for about the first three minutes.
readings. Keep the watch away from the types After that, it takes readings according to
● The altitude readings displayed by the
of items below. the watch’s auto measurement interval
watch are relative values that are
setting.
Permanent magnets (magnetic accessories, calculated based on barometric
etc.), metal objects, electrical household pressure measured by the watch’s
● Check the information at the link below
appliances (TVs, computers, cellphones, etc.) pressure sensor. This means that to find out how to configure the auto
barometric pressure changes due to measurement interval.
weather can cause altitude readings l Setting the Auto Measurement
taken at the same location to be Interval
different. Also note that the value ● To retrigger measurement, press (A).
displayed by the watch may be ● To return to the Timekeeping Mode,
different from the actual elevation and/ press (B).
or sea level elevation indicated for the
area where you are located. When Note
using the watch’s altimeter while
mountain climbing, it is recommended ● When you enter the Altitude Mode, the
that you regularly calibrate its readings
second hand indicates either
in accordance with local altitude
timekeeping seconds, or the
(elevation) indications.
differential between altitude
l Calibrating Altitude Readings measurements (whichever was
(Offset)
indicated the last time you were in the
● Check the information at the link below Altitude Mode). You can toggle
to find out about how to minimize between the two second hand
differences between readings functions by pressing (D).
produced by the watch, and values ● Measurement range: -700 to 10,000
provided by local altitude (elevation)
meters (-2,300 to 32,800 feet)
indications.
(Measurement unit: 1 meter (5 feet))
l Calibrating Altitude Readings Note that calibrating altitude readings
(Offset) will cause a change in the
l Altitude Reading Precautions measurement range.
● [- - -] will appear for the measured value
if it is outside the allowable range.

20
 Watch Operation Guide 5660
Interpreting Altitude Graph Contents
1. Enter the Altimeter Mode. Checking the Altitude
l Navigating Between Modes Differential from a Reference
2. Pull out the crown.
Point
This displays the current altitude and After you set a reference altitude, the second
enters the Altitude Offset Mode. hand of the watch will indicate the difference
50m* between your current altitude and the
reference altitude. This makes it easy to
measure the altitude difference between two
Current reading
points while climbing or trekking.
6 readings ago
● Setting the Altitude Differential
* 1 square (v) is 10 m. Measurement Range

Crown 1. Enter the Altimeter Mode.

l Navigating Between Modes
Calibrating Altitude 3. Rotate the crown to calibrate the 2. Pull out the crown.
Readings (Offset) displayed value to that of a local altitude
This displays the altitude for your current
(elevation) marker.
To minimize the difference between locally location.
indicated and measured values, you should Setting range: -3,000 to 10,000 meters (or
update the reference altitude value (offset) -9,840 to 32,800 feet)
before setting off and during treks or any other Setting unit: 1 meter (or 5 feet)
activities where you take altitude readings. ● To return the altitude setting to its initial
Also, you can ensure accurate measurements factory default, press (A) and (C) at the
by checking a map local altitude indications or same time.
some other source for your current location’s
4. Push the crown back in to complete the
altitude, and regularly calibrating watch
setting operation. Crown
readings with the latest information while
mountain climbing.
Note 3. Press (B) twice.
Note This displays the altitude differential
● If you do not perform any operation for measurement range.
about two minutes after pulling out the
● You can find out the altitude at your
crown, crown operations will
current location from signs, maps, on
automatically become disabled. If that
the Internet, etc.
happens, push the crown back in and
● Differences between actual altitude then pull it out again.
and watch readings can be caused by
the factors below.
ー Changes in barometric pressure
4. Rotate the crown to select either [100m] or
ー Changes in temperature caused by
[1000m].
variations in barometric pressure [100m]: ±100 meters (±328 feet) in 5-
and by elevation meter (16-foot) units
● Though altitude readings can be taken [1000m]: ±1000 meters (±3280 feet) in
without calibration, doing so may 50-meter (164-foot) units
produce readings that are very
different from indications by altitude 5. Push the crown back in to complete the
markers, etc. setting operation.

21
 Watch Operation Guide 5660
Note 4. While comparing the difference between Setting the Auto
the altitude you found on the map and the Measurement Interval
● If you do not perform any operation for altitude differential indicated by the
about two minutes after pulling out the watch’s second hand, advance towards You can select an auto measurement interval
crown, crown operations will your destination. of either five seconds or two minutes.
automatically become disabled. If that ● When the altitude differential you found 1. Enter the Altimeter Mode.
happens, push the crown back in and
on the map is the same as that indicated
then pull it out again. l Navigating Between Modes
by the second hand, it means you are
close to your destination. 2. Pull out the crown.
● Measuring Altitude Example: Altitude differential of -30 m (-98 This displays the altitude for your current
feet) (-300 m (-984 feet)) location.
1. Use the contour lines on your map to
determine the altitude differential between Unit: m

your current location and your destination. 100 50

2. Take an altitude reading of your current

location. Range: ±100 m (1000 m)
0

l Checking the Current Altitude (±328 feet (3280 feet))

3. Hold down (D) for at least two seconds to Altitude differential

indicator Crown
set your current location’s altitude as the
−100 −50

reference altitude.
3. Press (B).
This displays [DIFF RESET] n [RESET] This causes the auto measurement
and then your current altitude. Note
interval to appear on the display.
● The second hand (Altitude Differential
Indicator) will indicate the difference
● You can toggle between the two
between the reference altitude and the second hand functions by pressing
current altitude reading. At this time the (D).
second hand should indicate ±0 m (±0 l Checking the Current Altitude
feet). ● The second hand points to r (over) if
the current altitude differential is
Altitude differential indicator
4. Rotate the crown to select [0’05] or [2’00]
greater than the setting value, or s
as the auto measurement interval.
(under) if it is lower than the setting
value. [0’05]: Readings taken every second for
If either of these is indicated while the first three minutes, and then every five
using the ±100 m (328 feet) seconds for about the next one hour.
measurement range, change the [2’00]: Readings taken every second for
range setting to ±1000 m (3280 feet). the first three minutes, and then every two
Current location altitude ● The second hand will move to 9 o’clock minutes for about the next 12 hours.
if a reading is outside the allowable 5. Push the crown back in to complete the
altitude measurement range (-700 m to setting operation.
10,000 m (-2,300 to 32,800 feet)), or if
a reading error occurs.

22
 Watch Operation Guide 5660
● Auto Altitude Data Recording
Note Specifying the Altitude
The altitude data described below is recorded
Measurement Unit
automatically while the watch is in the
● If you do not perform any operation for
Altimeter Mode. One record each is You can select either meters (m) or feet (ft) as
about two minutes after pulling out the
maintained in memory for each of these items. the Altimeter Mode display unit.
crown, crown operations will
automatically become disabled. If that E
happens, push the crown back in and Important!
then pull it out again. Start point
● The watch will automatically return to C D
● When Tokyo (TYO) is set as the Home
the Timekeeping Mode if you do not City, the altitude unit is fixed as meters
perform any operation in the Altimeter A
B
(m) and cannot be changed.
Mode for about one hour while [0’05] is
selected as the measurement interval F
End point
or about 12 hours while [2’00] is 1. Enter the Altimeter Mode.
selected. l Navigating Between Modes
High Altitude (MAX): E
2. Pull out the crown.
Low Altitude (MIN): F
This displays the current altitude and
Recording Altitude Readings Cumulative Ascent (ASC): A+C* enters the Altitude Offset Mode.

Use the procedure below to record altitude Cumulative Descent (DSC): B+D*
measurements manually. Auto * Cumulative ascent and cumulative descent
measurements are also recorded values are updated whenever there is a
automatically. difference of at least ±15 m (±49 feet) from
● Use the Altitude Record Recall Mode to one reading to the next.
view or delete records.
Note
l Viewing Altitude Records
Crown
● Recording Altitude Data Manually ● Auto recording ends when you exit the
Altimeter Mode. Re-entering the 3. Press (B) three times.
1. Enter the Altimeter Mode. Altimeter Mode restarts recording of This causes [UNIT] to appear, with [m] or
l Navigating Between Modes cumulative values from where it was [ft] flashing.
2. Hold down (A) for at least two seconds stopped when you last exited the
until [REC] stops flashing on the display. Altimeter Mode.

This records the current altitude, date,

and time.
● There is enough memory to hold up to
30 altitude records.
● Recording altitude data when there are 4. Rotate the crown to select an altitude unit.
already 30 records in memory [m]: Meters
automatically deletes the oldest record
[ft]: Feet
to make room for the new one.
Meters Feet

5. Push the crown back in to complete the

setting operation.

Note

● If you do not perform any operation for

about two minutes after pulling out the
crown, crown operations will
automatically become disabled. If that
happens, push the crown back in and
then pull it out again.

23
 Watch Operation Guide 5660
Altitude Reading Precautions Barometric Pressure Checking the Current
Barometric Pressure
Effects of Temperature Measurement
When taking altitude readings, take the steps
below to keep the watch at as stable a 1. Enter the Barometer Mode.
You can use the Barometer Mode to take a
temperature as possible. Changes in l Navigating Between Modes
reading of the barometric pressure at your
temperature can affect altitude readings. Entering the Barometer Mode starts
current location, and to track reading changes
● Take readings with the watch on your wrist. measurement, and displays the
and trends.
barometric pressure at your current
● Take readings in an area where temperature
location and a barometric pressure graph.
is stable.
● After you enter the Barometer Mode,
Altitude Readings the watch takes readings about every
● Do not use this watch while skydiving, hang five seconds for three minutes. After
gliding, paragliding, gyrocopter flying, glider that, a measurement is taken about
flying, or engaged in other activities where every two minutes.
altitude changes suddenly.
Barometric pressure graph
● Altitude readings produced by this watch are
not intended for special-purpose or industrial
level use.
● In an aircraft, the watch measures the in-cabin
Important!
pressurized air pressure, so readings will not
match altitudes announced by the crew.
● Check the information at the link below
Altitude Readings (Relative Altitude) to find out how to ensure correct
This watch uses International Standard readings. Barometric pressure

Atmosphere (ISA) relative altitude data defined l Calibrating Barometric Pressure

Readings (Offset)
● To retrigger measurement, press (A).
by the International Civil Aviation Organization
(ICAO). Barometric pressure generally becomes l Barometric Pressure Reading ● To return to the Timekeeping Mode,
lower as altitude increases. Precautions hold down (B) for at least two seconds.
Correct measurement may not be possible
under the conditions below.
Note
● During unstable atmospheric conditions ● When you enter the Barometer Mode,
● During sudden temperature changes the second hand indicates either
● After the watch has been subjected to strong timekeeping seconds, or the
impact differential between barometer
measurements (whichever was
indicated the last time you were in the
Barometer Mode).
You can toggle between the two
second hand functions by pressing
(D).
● The watch will automatically return to
the Timekeeping Mode from the
Barometer mode if you do not perform
any operation for about one hour.
● The measurement range is 260 hPa to
1,100 hPa (7.65 inHg to 32.45 inHg) (1
hPa (0.05 inHg) units). [- - -] will appear
for the measured value if it is outside
the allowable range.

24
 Watch Operation Guide 5660
Checking Changes in Checking the Change in Sudden Barometric Pressure
Barometric Pressure Over Barometric Pressure Change Indications
Time between Two Readings
Whenever the watch detects a significant
The watch displays a graph of 20 hours of When you perform the procedure below in the change in air pressure readings (due to
barometric pressure readings taken every two Barometer Mode, the second hand indicates sudden ascent or descent, or to the passage
the difference between the current barometric of a low pressure or high pressure area), it will
hours. The square (v) at the far right of the
pressure measurement and the last auto beep to let you know. An arrow will also flash
graph indicates the latest barometric pressure
measurement value (taken at two-hour on the display at this time if the watch is in the
reading.
intervals). Barometer Mode, or if it is in the Timekeeping
Mode with the barometric pressure graph
1. Enter the Barometer Mode. displayed. The arrow that appears shows the
Barometric pressure l Navigating Between Modes direction of the pressure change. These alerts
(1 hPa per division) are called “Barometric Pressure Change
2. Press (D). Indications”.
Time The second hand indicates the
(2 hours per division) This
barometric pressure differential (Pressure Means this:
indicator:
Differential Indicator).
Example: Barometric pressure differential Sudden drop in pressure
of -3 hPa (approximately -0.09 inHg)

● Predicting Upcoming Weather Unit: hPa Sudden rise in pressure

A trend
Means this: Sustained rise in pressure,
like this:
10 5

shifting to a fall
Rising barometric pressure,
which indicates that upcoming Sustained fall in pressure, shifting
weather probably will be fair. 0
Range: ±10 hPa
to a rise
(1 hPa units)
Falling barometric pressure,
which indicates that upcoming Important!
Pressure
weather probably will be bad. Differential Indicator
−10 −5
● To ensure correct barometric pressure
Note change indicator operation, enable it in
a location where the altitude is
● Large changes in barometric pressure constant (such as a lodge, camp area,
Note
and/or temperature can cause past or on the ocean).
data readings to be plotted outside of ● A change in altitude causes a change
the visible area of the graph. Though
● You can toggle between the two
second hand functions by pressing in air pressure. Because of this, correct
plots are not visible, the data is still readings are impossible. Do not take
maintained in watch memory. (D).
readings while ascending or
l Checking the Current Barometric
● The barometric pressure graph is not descending a mountain, etc.
Pressure
displayed while Barometric Pressure
Change Indications are displayed. ● The second hand points to r (over) if
l Sudden Barometric Pressure the current barometric pressure
Change Indications differential is greater than +10 hPa (0.3
inHg), or s (under) if it is less than -10
hPa (-0.3 inHg).
● A reading that is outside the allowable
measurement range of 260 hPa to
1,100 hPa (7.65 inHg to 32.45 inHg),
or any measurement error will cause
the second hand to move to 9 o’clock.

25
 Watch Operation Guide 5660
1. Enter the Barometer Mode. Calibrating Barometric Specifying the Barometric
l Navigating Between Modes Pressure Readings (Offset) Pressure Unit
2. Hold down (D) for at least two seconds. The watch’s pressure sensor is adjusted at the You can specify either hectopascals (hPa) or
If this turns on barometric pressure factory and normally does not require inches of mercury (inHg) as the display unit for
change indication, [INFO ON] will stop calibration. However, you can calibrate the barometric pressure values.
flashing and then the [BARO] indicator will displayed value if you notice major errors in
appear on the display. readings. Important!

Important! ● When Tokyo (TYO) is the Home City,

the barometric pressure unit is fixed as
● The watch will not be able to produce hectopascals (hPa) and cannot be
correct barometric pressure readings if changed.
you make a mistake during the
calibration procedure. Check to make
3. To disable barometric pressure change sure that the value you use for 1. Enter the Barometer Mode.
indication, hold down (D) again for at least calibration produces correct pressure
two seconds. l Navigating Between Modes
readings.
2. Pull out the crown.
Note This displays the current barometric
1. Enter the Barometer Mode. pressure.
● If Barometric Pressure Change
l Navigating Between Modes
Indications are on, barometric
pressure readings are taken every two 2. Pull out the crown.
minutes even while the watch is not in This displays the current barometric
the Barometer Mode. pressure and enters the Barometric
● The Barometric Pressure Change Pressure Offset Mode. Crown
Indication becomes disabled
automatically 24 hours after it is 3. Press (B).
enabled.
This causes [UNIT] to appear, with [hPa]
● You will not be able to turn on or [inHg] flashing.
barometric pressure change indication
if the watch’s battery level is low. Crown

● Low battery power will also cause

barometric pressure change indication
3. Rotate the crown to change the value.
to turn off automatically. Setting range: 260 to 1,100 hPa (or 7.65
inHg to 32.45 inHg)
Setting unit: 1 hPa (or 0.05 inHg)
4. Rotate the crown to select a barometric
● To return the barometric pressure pressure unit.
setting to its initial factory default, press
[hPa]: Hectopascals
(A) and (C) at the same time.
[inHg]: Inches of mercury
4. Push the crown back in to complete the
setting operation. Hectopascals Inches of mercury

Note

● If you do not perform any operation for

about two minutes after pulling out the 5. Push the crown back in to complete the
crown, crown operations will setting operation.
automatically become disabled. If that
happens, push the crown back in and
then pull it out again.

26
 Watch Operation Guide 5660
Note Temperature Checking the Current
Temperature
● If you do not perform any operation for Measurement
about two minutes after pulling out the
1. Enter the Thermometer Mode.
crown, crown operations will The watch can be used to take current air
l Navigating Between Modes
automatically become disabled. If that temperature readings.
happens, push the crown back in and Entering the Thermometer Mode will start
then pull it out again. temperature measurement and display
the result.
● After you enter the Thermometer Mode,
the watch takes readings about every
Barometric Pressure five seconds for three minutes. After
Reading Precautions that, a measurement is taken about
every two minutes.
● The barometric pressure graph produced ● To retrigger measurement, press (A).
by this watch can be used to obtain an idea
of upcoming weather conditions. However,
this watch should not be used in place of
precision instruments required for official Important!
weather prediction and reporting.
● Pressure sensor readings can be affected
● Check the information at the link below
by sudden changes in temperature. to find out how to ensure correct
Because of this, there may be some error in readings.
the readings produced by the watch. l Temperature Reading Temperature
Precautions

Note

● The watch will automatically return to

the Timekeeping Mode if you do not
perform any operation in the
Thermometer Mode for about one
hour.
● The measuring range is -10.0 °C to
60.0 °C (14.0 °F to 140.0 °F) (0.1 °C
(0.2 °F) units). [- - .-] will appear for the
measured value if it is outside the
allowable range.
● To return to the Timekeeping Mode,
hold down (B) for at least two seconds.

27
 Watch Operation Guide 5660
Calibrating Temperature Specifying the Temperature Temperature Reading
Readings (Offset) Measurement Unit Precautions
The watch’s temperature sensor is adjusted at You can select either Celsius (°C) or Body temperature, direct sunlight, and
the factory and normally does not require Fahrenheit (°F) as the temperature display humidity all have an effect on temperature
calibration. However, you can calibrate the unit. readings. To help ensure more accurate
displayed value if you notice major errors in temperature readings, remove the watch from
readings. Important! your wrist, wipe it dry of any moisture, and
place it in a well-ventilated location not
Important! ● When Tokyo (TYO) is the Home City, exposed to direct sunlight. You should be able
the temperature unit is fixed as Celsius to take temperature readings after about 20 to
● Check to make sure that the value you (°C) and cannot be changed. 30 minutes.
use for calibration produces correct
temperature readings.
● Before calibrating the temperature 1. Enter the Thermometer Mode.
reading, remove the watch from your l Navigating Between Modes
wrist and leave it in the area where you
plan to measure temperature for about 2. Pull out the crown.
20 or 30 minutes to allow the case This displays the current temperature.
temperature to become the same as
the air temperature.

1. Enter the Thermometer Mode.

l Navigating Between Modes Crown

2. Pull out the crown.

3. Press (B).
This displays the current temperature.
This causes [UNIT] to appear, with [°C] or
[°F] flashing.

Crown

3. Rotate the crown to calibrate the

temperature value. 4. Rotate the crown to select a temperature
unit.
Calibration unit: 0.1 °C (0.2 °F)
[°C]: Celsius
● To return the barometric pressure
setting to its initial factory default, press [°F]: Fahrenheit
(A) and (C) at the same time.
Celsius Fahrenheit
4. Push the crown back in to complete the
setting operation.

Note
5. Push the crown back in to complete the
● If you do not perform any operation for setting operation.
about two minutes after pulling out the
crown, crown operations will Note
automatically become disabled. If that
happens, push the crown back in and ● If you do not perform any operation for
then pull it out again. about two minutes after pulling out the
crown, crown operations will
automatically become disabled. If that
happens, push the crown back in and
then pull it out again.

28
 Watch Operation Guide 5660
● Auto Recorded Data
Viewing Altitude Note
After displaying an auto recorded data record,
Records ● If there is no data left in memory due to
you can navigate between the record’s data
screens as shown below.
a data delete operation, error, or some
You can use the Altitude Record Recall Mode other reason, [- - - -] or [0] will appear High altitude and low altitude
to view manually recorded and auto recorded on the display.
Example: High altitude
data. ● If the cumulative ascent (ASC) or
l Recording Altitude Readings cumulative descent (DSC) value
Data type Recording date
exceeds 99,999 m (327,995 feet), it 1 second
will revert to 0 and continue from there.

Viewing Recorded Data ● Pressing (D) returns to the top screen

(record number, DSC, ASC, MAX, or D 2 seconds

MIN) of the data that you are viewing.

1. Enter the Altitude Record Recall Mode. Altitude Time
● If you do not perform any operation for
l Navigating Between Modes
about three minutes while in the
This displays a record of data recorded in
Altitude Record Recall Mode, the 2 seconds
the Altimeter Mode.
watch automatically returns to the
2. Use (A) and (C) to display the data you Timekeeping Mode.
want to view. Cumulative ascent and cumulative
descent
● Holding down (A) or (C) scrolls at high ● Manually Recorded Data
speed. Example: Cumulative ascent
After displaying the top screen of a manually
recorded data record (01 through 30), the Date when
Data type accumulation started.
Manually Recorded Data record’s data screens appear in sequence as
1 second
shown below.
A*
Example: Manually recorded Record 01

C*
Record number Recording date D 2 seconds
Cumulative altitude
1 second

A C C A
D 2 seconds
Auto Recorded Data
Altitude Time

Total Descent High Altitude

2 seconds

A C C A

Total Ascent Low Altitude

* Each press of a button scrolls to the top

screen of the next manually recorded
data record, numbered from 1 ([-01-]) to
a maximum of 30 ([-30-]).

29
 Watch Operation Guide 5660
Deleting Data Stopwatch Measuring a Split Time
● Deleting a Particular Record
1. Enter the Stopwatch Mode.
The Stopwatch Mode lets you measure
1. Enter the Altitude Record Recall Mode. elapsed time up to 24 hours in 1/100 of a l Navigating Between Modes
l Navigating Between Modes second units. 2. Use the operations below to measure
2. Use the (A) and (C) buttons to scroll It can also measure split times. elapsed time.
through the top screens of the records and A Start
display the one you want to delete .

3. Hold down the (D) for at least two C Split

seconds. Release the button as soon as

[CLEAR] stops flashing. C Split release

This deletes the record you selected.

A Stop

Hours, minutes, seconds, 1/100 seconds

● Note that holding down (D) for more Measuring Elapsed Time
than five seconds will delete all data.

● Deleting All Records 1. Enter the Stopwatch Mode.

Hold down (D) for at least five seconds until l Navigating Between Modes 3. Press (C) to reset the measurement time
[CLEAR ALL] stops flashing. This indicates to all zeros.
2. Use the operations below to measure
that all data was deleted. elapsed time.
A Start
Timing the First and Second
A Stop
Place Finishers

A Resume
1. Enter the Stopwatch Mode.
l Navigating Between Modes

A Stop 2. Use the operations below to measure

elapsed time.
Hours, minutes, seconds, 1/100 seconds
A Start

C 1st Finisher*

A 2nd Finisher*

* Displays the time of the first finisher.

3. Press (C) to reset the measurement time
to all zeros. Hours, minutes, seconds, 1/100 seconds

3. Press (C) to display the time of the second

place finisher.

4. Press (C) to reset the measurement time

to all zeros.

30
 Watch Operation Guide 5660
Timer Using the Timer Hand Alignment
1. Enter the Timer Mode.
Adjustment
The timer counts down from a start time
specified by you. A beeper sounds when the l Navigating Between Modes
Strong magnetism or impact can cause the
end of the countdown is reached. 2. Use the operations below to perform a
time indicated by the analog hands to become
The beeper will not sound if battery power timer operation.
different from the time on the display. If this
●

is low. A Start happens, adjust hand alignment.

(Countdown starts)

Adjusting Hand Alignment

A Pause

1. Enter the Timekeeping Mode.

A Resume l Navigating Between Modes

2. Pull out the crown.

(Time up)
This causes [CITY] to flash on the display
● A beeper will sound for 10 seconds to and the second hand to move to the
let you know when the end of a current Home City.
countdown is reached. Second hand
Setting a Start Time ● You can reset a paused countdown to
its start time, by pressing (C).
The start time can be set in 1-minute units up
to 60 minutes. 3. Press any button to stop the tone.

1. Enter the Timer Mode.

l Navigating Between Modes Crown

2. Pull out the crown. Home City

This causes the minutes digits to flash.
Minutes 3. Hold down (A) for at least five seconds.
Release the button when [HAND ADJ]
starts to flash.
This indicates that hand alignment
adjustment has started.

Crown
● [HAND SET] will flash first on the
display about 0.5 seconds after you
hold down the (A) button. Keep the
3. Rotate the crown to change the timer start
button depressed until [HAND ADJ]
time minutes.
flashes on the display.
4. Push the crown back in to complete the
After 0.5 seconds
setting operation.
After five seconds

Note

● If you do not perform any operation for

about two minutes after pulling out the
crown, crown operations will
automatically become disabled. If that 4. After all the hands move to 12 o’clock,
happens, push the crown back in and push the crown back in.
then pull it out again. This returns the hands to normal
timekeeping.

31
 Watch Operation Guide 5660
Note Other Settings 5. Push the crown back in to complete the
setting operation.
● If you do not perform any operation for
about two minutes after pulling out the This section explains other watch settings you
Note
crown, crown operations will can configure.
automatically become disabled. If that ● If you do not perform any operation for
happens, push the crown back in and about two minutes after pulling out the
then pull it out again. Enabling the Button crown, crown operations will
Operation Tone automatically become disabled. If that
happens, push the crown back in and
Important! Use the procedure below to enable or disable then pull it out again.
the tone that sounds when you press a button. ● Note that alarm and timer tones will still
● After hand position adjustment is sound even while the operation tone is
complete, check to make sure that the 1. Enter the Timekeeping Mode.
muted.
proper time is being indicated in the l Navigating Between Modes
Timekeeping Mode by the hands and 2. Pull out the crown.
on the display. If the hands are
This causes [CITY] to flash on the display
misaligned, perform steps 2 through 4
and the second hand to move to the
again.
current Home City.

Second hand

Crown

Home City

3. Press (B) twice.

This causes [KEY♪] or [MUTE] to flash on
the display.

4. Rotate the crown to select either [KEY♪]

or [MUTE].
[KEY♪]: Operation tone enabled.
[MUTE]: Operation tone muted.

32
 Watch Operation Guide 5660
Configuring Power Saving Other Information Specifications
Function Settings
Accuracy :
This section provides non-operational ±15 seconds per month average when time
1. Enter the Timekeeping Mode. information you also need to know. Refer to adjustment using signal reception is not
l Navigating Between Modes this information as required. possible.
2. Pull out the crown. Basic Functions :
This causes [CITY] to flash on the display Analog
and the second hand to move to the City Table Hour, minute (moves every 10 seconds),
current Home City. second
City Time
City Name Digital
Second hand code Zone
Hour, minute, second, month, day, day of
Coordinated Universal
UTC the week
Time 0
Barometric pressure graph
LON* London
a.m. (A)/p.m. (P)/24-hour timekeeping
PAR* Paris +1
Full Auto Calendar (2000 to 2099)
ATH* Athens +2
Crown JED Jeddah +3 Signal Receive Functions :
THR Tehran +3.5 Auto receive, manual receive
Last receive date and time display
Home City
DXB Dubai +4
KBL Kabul +4.5 Auto summer time switching
3. Press (B) six times. Auto transmitter selection (for JJY, MSF/
KHI Karachi +5
This displays [P.SAVE]. DCF77)
DEL Delhi +5.5
Receivable call signs:
KTM Kathmandu +5.75
JJY (40 kHz/60 kHz), WWVB (60 kHz), MSF
DAC Dhaka +6
(60 kHz), DCF77 (77.5 kHz), BPC (68.5
RGN Yangon +6.5
kHz)
BKK Bangkok +7
Auto Receive enable/disable
HKG* Hong Kong +8
TYO* Tokyo +9 Digital Compass :
4. Rotate the crown to turn the setting on or ADL Adelaide +9.5 Measurement range: 0° to 359°
off. SYD Sydney +10 Measurement Units: LCD: 1°, Analog: 6°
[ON]: Power Saving enabled. NOU Noumea +11 Continuous Bearing Measurement (1
minute)
[OFF]: Power Saving disabled. WLG Wellington +12
North Indication Hand
PPG Pago Pago -11
5. Push the crown back in to complete the Compass calibration (2-point calibration,
HNL* Honolulu -10
setting operation. magnetic declination angle)
ANC* Anchorage -9
LAX* Los Angeles -8 Altimeter (relative altitude) :
Note
DEN* Denver -7 Measuring range: -700 to 10,000 m (or
● If you do not perform any operation for CHI* Chicago -6 -2,300 to 32,800 ft.)
about two minutes after pulling out the NYC* New York -5 Display range: -3,000 to 10,000 m (or -9,840
crown, crown operations will YHZ Halifax -4 to 32,800 ft.)
automatically become disabled. If that RIO Rio de Janeiro -3 (Altitude calibration can be used to display
happens, push the crown back in and any 10,700 m within the range above.)
RAI Praia -1
then pull it out again. Measuring unit: 1 m (or 5 ft.)
* Cities where time calibration signal
Auto measurement interval (2 minutes, 5
● For details about Power Saving, refer reception is possible.
seconds)
to the information below. ● The information in the above table is current Altitude calibration
l Power Saving Function as of January 2021. Altitude graph
● Time zones may change and UTC Altitude differential measurement (-100 to
differentials may become different from +100 m/-1,000 to +1,000 m (or -325 to +325
those shown in the table above. ft./-3,280 to +3,280 ft.))
Altitude Memory
Manually Recorded Data
One-press recording of altitude, date
(year, month, day), and time. Up to 30
records.
Auto Record Data
One record of high altitude, low
altitude, cumulative ascent, cumulative
descent

33
 Watch Operation Guide 5660
Barometer : Alarm : Troubleshooting
Measurement range: 260 to 1,100 hPa (or Time alarms
7.65 to 32.45 inHg) Number of alarms: 5
Display range: 260 to 1,100 hPa (or 7.65 to Setting units: Hours, minutes
32.45 inHg) Alarm tone duration: 10 seconds Signal Reception (Time
Measurement unit: 1 hPa (or 0.05 inHg) Hourly time signal: Beep every hour on the
Calibration Signal)
Barometric pressure adjustment hour
Barometric pressure graph
World Time : Q1 The watch cannot perform a receive
Barometric pressure differential indicator
Current time in 29 cities (29 time zones), operation.
Barometric pressure change indications
and UTC (Coordinated Universal Time)
Temperature : time Is the watch’s battery charged?
Measuring range: -10.0 to 60.0 °C (or 14.0 Summer time
to 140.0 °F) City swapping Signal reception is not possible while
Display range: -10.0 to 60.0 °C (or 14.0 to One-touch UTC display battery power is low. Keep the watch
140.0 °F) exposed to light until it recharges
Other : sufficiently.
Measuring unit: 0.1 °C (or 0.2 °F)
Double LED light: LED light for dial and LED l Charging
Temperature Correction
backlight for LCD (with Full Auto Light,
Sensor Accuracy : Super Illuminator, afterglow, afterglow Is the watch in the Timekeeping Mode?
Direction sensor duration setting (1.5 seconds, 3 seconds));
Time signal receive is performed only
Measurement accuracy: Within ±10° alarm testing; automatic hand position
while the watch is in the Timekeeping
(Guaranteed accuracy temperature correction; power saving; charge level
Mode. Return to the Timekeeping Mode.
range: 10 °C to 40 °C (50 °F to 104 °F)) (battery) indicator; operation tone enable/
l Navigating Between Modes
Bearing hand indication: Within ±2 disable; hand shift
gradations
Power Supply : Is your Home City setting correct for your
Pressure sensor
Solar panel and one rechargeable battery location?
Measurement accuracy: Within ±3 hPa
Battery operating time: Approximately 6 The watch will not indicate the correct time
(0.1 inHg)
months if the Home City setting is wrong. Change
(Altimeter measurement accuracy:
Conditions: your Home City setting so it correctly
Within ±75 m (246 ft.))
Illumination: 1.5 seconds/day reflects your location.
● Guaranteed accuracy temperature
Beeper: 10 seconds/day l Setting a Home City
range: -10 °C to 40 °C (14 °F to 104 °F)
Digital Compass Operations: 20 times/
● Strong impact or prolonged exposure to month After checking the above, the watch still
temperature extremes may negatively Mountain climbing: Once/month cannot perform a receive operation.
affect accuracy. (Altitude readings: Approximately 1
Temperature Sensor Time calibration signal reception is not
hour; Barometric pressure change
Measurement accuracy: Within ±2 °C possible under the conditions described
indication measurements:
(3.6 °F) below.
Approximately 24 hours)
(Guaranteed accuracy temperature Barometric Pressure Graph:
● When watch is at Level 2 power saving
range: -10 °C to 60 °C (14 °F to 140 °F)) Measurement every 2 hours ● When the crown is pulled out
Stopwatch : Time signal reception: 4 minutes/day ● Timer countdown operation in progress
Display: 18 hours/day
Measuring unit: 1/100 second If successful reception is not possible for
Measuring range: some reason, you can adjust the time and
23 hours, 59 minutes, 59.99 seconds (24 Specifications are subject to change without day settings manually.
hours) notice.
Measurement Functions:
Elapsed time, cumulative time, split
times, 1st and 2nd place finisher times

Timer :
Setting unit: 1 minute
Measuring range: 60 minutes
Countdown unit: 1 second
Time up alert duration: 10 seconds

34
 Watch Operation Guide 5660
Q2 The signal receive operation always Altitude Measurement Digital Compass
fails.

Q1 Readings produce different results at Q1 The entire display is flashing.

Is the watch in a location that is appropriate
the same location.
for signal reception? Abnormal magnetism has been detected.
Watch readings are different from
Move away from any potential source of
Check your surroundings and move the altitude information available from
strong magnetism and try taking a reading
watch to a location where signal reception other sources.
again.
is better. Correct altitude readings are not
l Digital Compass Reading Precautions
l Appropriate Signal Reception Location possible.
● If the display flashes again, it could mean
Did you avoid touching the watch while the Relative altitude is calculated based on that the watch itself has become
receive operation was in progress? changes in barometric pressure measured by magnetized. Move away from any potential
the watch’s pressure sensor. This means that source of strong magnetism, perform 2-
Minimize movement of the watch and do barometric pressure changes can cause point calibration, and then try taking a
not perform any watch operation while a readings taken at the same location to be reading again.
receive operation is in progress. different. Also note that the value displayed by l Calibrating Compass Readings
the watch may be different from the actual
Is there an alarm configured to sound elevation and/or sea level elevation indicated
during the same period that the signal Q2 [ERR] appears during measurement.
for the area where you are located. When
receive operation is performed? using the watch’s altimeter while mountain There is a problem with the sensor or there
climbing, it is recommended that you regularly may be a source strong magnetic force
Receive stops if an alarm operation starts
calibrate its readings in accordance with local nearby. Move away from any potential source
while it is being performed. Disable the
altitude (elevation) indications. of strong magnetism and try taking a reading
alarm.
l Calibrating Altitude Readings (Offset) again. If [ERR] keeps appearing after multiple
l Turning Off an Alarm or the Hourly
measurement attempts, contact a CASIO
Time Signal
service center or your original retailer.
Q2 Following a relative altitude reading,
Is the signal transmitter in your area the watch’s second hand points to 9 l Digital Compass Reading Precautions
transmitting a signal? o’clock.
Q3 [ERR] appears following 2-point
The transmitter of the time calibration may The second hand will move to 9 o’clock if a
calibration.
not be transmitting a signal. reading is outside the allowable altitude
Try again later. measurement range (-700 m to 10,000 m [ERR] on the display could indicate a sensor
(-2,300 to 32,800 feet)). If [ERR] is displayed, problem.
there may be a problem with the sensor. If [ERR] disappears after about one second,
Q3 Signal reception should have been ●

successful, but the watch’s time and/ l Checking the Altitude Differential from a try performing 2-point calibration again.
Reference Point
or day is wrong. ● If [ERR] keeps appearing after multiple
attempts, contact a CASIO service center or
Is the indicated time off by one hour or by Q3 [ERR] appears during measurement. your original retailer.
30 minutes? There may be a problem with the sensor. Try
The watch may be using the wrong time taking another measurement. Q4 Direction information indicated by the
offset. Specify the area you want to use as If [ERR] keeps appearing after multiple watch is different from that indicated
your Home City. measurement attempts, contact a CASIO by a backup compass.

l Setting a Home City service center or your original retailer. Move away from any potential source of
strong magnetism, perform 2-point
Is the indicated hour and/or minute wrong? calibration, and then try taking a reading
The hour hand and/or minute hand may again.
be out of alignment. Perform the l Calibrating Compass Readings
procedure under “Hand Alignment l Digital Compass Reading Precautions
Adjustment” to auto adjust hour and
minute hand alignment. Q5 Readings at the same location
l Hand Alignment Adjustment produce different results.
Cannot take readings indoors.
After checking the above, the time and/or
day settings is still wrong. Move away from any potential source of
strong magnetism and try taking a reading
Adjust time and day settings manually. again.
l Using Watch Operations to Adjust the l Digital Compass Reading Precautions
Time Setting

35
 Watch Operation Guide 5660
Barometric Pressure Alarm Q5 Hands are stopped and buttons do
not work.
Measurement
Q1 The alarm does not sound. The watch is in the charge recovery mode.
Wait until the recovery process is complete
Q1 Following a relative barometric (for about 15 minutes). The watch will recover
pressure reading, the watch’s Is the watch’s battery charged?
more quickly if you place it in a brightly lit
second hand points to 9 o’clock. Keep the watch exposed to light until it location.
The second hand will move to 9 o’clock if a recharges sufficiently.
reading is outside the allowable barometric l Charging Q6 Why is the current time indicated by
pressure measurement range (260 hPa to the watch is off by a certain amount
1,100 hPa (7.65 inHg to 32.45 inHg)). If [ERR] The crown is pulled out.
of time (nine hours, three hours and
appears on the display, there may be a The alarm will not sound while the crown 15 minutes, etc.)?
problem with the sensor. is pulled out. Push the crown back in to its
The city setting is not correct. Select the
l Checking the Change in Barometric normal position.
Pressure between Two Readings correct setting.

Is the alarm enabled? l Setting a Home City

Q2 [ERR] appears during measurement. Enable the alarm.

Q7 The current time indicated by the
There may be a problem with the sensor. Try l Configuring Alarm Settings watch is off by one hour or 30
taking another measurement. If [ERR] keeps minutes.
appearing after multiple measurement
attempts, contact a CASIO service center or The summer time setting may not be correct.
Hand Movement and Watch Select the correct setting.
your original retailer.
Screen Indications l Setting a Home City

Temperature Measurement Q1 I don’t know what mode the watch is Q8 The time indicated by the hands is
in. different from the displayed time.

Q1 [ERR] appears during measurement. You can determine the current mode by Strong magnetism or impact can cause the
checking the watch display. Use (B) to hands to go out of alignment. Adjust hand
There may be a problem with the sensor. Try navigate between modes. alignment.
taking another measurement. If [ERR] keeps
l Navigating Between Modes l Hand Alignment Adjustment
appearing after multiple measurement
attempts, contact a CASIO service center or
your original retailer. Q2 The second hand is jumping at two-
second intervals. Crown Operations
Battery power is low. Keep the watch exposed
World Time to light until it recharges sufficiently. Q1 Nothing happens when I rotate the
l Charging crown.

Q1 The time for a World Time City is not If you do not perform any operation for about
Q3 All hands are stopped and buttons do two minutes after pulling out the crown
correct.
not work. (approximately 30 minutes in the case of hand
The summer time setting (standard time/ and day indicator alignment), crown
The battery is dead. Keep the watch exposed
summer time) may be wrong. operations will automatically become
to light until it recharges sufficiently.
l Specifying a World Time City disabled. Push the crown back in to its normal
l Charging
position and then pull it out again to re-enable
crown operations.
Q4 The hands suddenly start moving at l Using the Crown
high speed.

This is due to the reason (or one of the

reasons) below, and does not indicate
malfunction. Simply wait until normal hand
movement resumes.
● The watch is recovering from a power
saving state.
l Power Saving Function
● A time calibration signal is being received
and the time setting is being adjusted.
l Time Adjustment Using a Time Signal

36
 Watch Operation Guide 5660
Charging

Q1 The watch does not work even

though it is exposed to light.

The watch stops operating whenever the

battery goes dead. Keep the watch exposed
to light until it recharges sufficiently.
l Checking the Charge Level

Q2 [RECOVER] is flashing on the

display.

The watch is in the charge recovery mode.

Wait until the recovery process is complete
(about 15 minutes). The watch will recover
more quickly if you place it in a brightly lit
location.
● If a sensor measurement operation,
illumination and/or other power-intensive
functions are used within a short period of
time, the charging capacity of the battery
drops and causes the watch to go into a
charge recovery mode. Function availability
is temporarily limited, but functionality
returns after the battery recovers.
l Checking the Charge Level

Q3 [CHARGE] is flashing on the digital

display.

The charge level of the watch is extremely low.

Immediately expose the watch to light to
charge it.
l Checking the Charge Level

Other

Q1 I can’t find the information I need

here.

Visit the website below.

https://world.casio.com/support/

37