Casio 3422 User manual

Operation Guide 3422
E-9
xWhen DST is turned on, the UTC offset setting range is –11.0 to +15.0, in 0.5-
hour units.
4. Press Ato exit the setting screen.
xThe day of the week is displayed automatically in accordance with the date (year,
month, and day) settings.
Daylight Saving Time (DST)
Daylight Saving Time (summer time) advances the time setting by one hour from
Standard Time. Remember that not all countries or even local areas use Daylight
Saving Time.
E-8
3. When the setting you want to change is flashing, use Dand Bto change it as
described below.
Screen To do this: Do this:
Reset the seconds to Press D.
Toggle between Daylight Saving Time
( ) and Standard Time ( ) Press D.
Specify the UTC offset Use D(+) and B(–).
Change the hour or minutes
Use D(+) and B(–).
Change the year
Change the month or day
xSee “Daylight Saving Time (DST)” on page E-9 for details about DST setting.
xThe UTC offset setting range is –12.0 to +14.0, in 0.5-hour units.
E-7
To set the time and date
1. In the Timekeeping Mode, hold down Auntil the
seconds start to flash, which indicates the setting
screen.
2. Press Cto move the flashing in the sequence shown
below to select other settings.
Seconds DST
Day
Hour
Minutes
Home Time Zone
Month Year
C
C
CC C C
CC
Home time zone
E-6
Timekeeping
Use the Timekeeping Mode to set and view the current
time and date.
Read This Before You Set the Time and Date!
The times displayed in the Timekeeping Mode and World
Time Mode are linked. Because of this, make sure you
select a Home Time zone before you set the time and date.
Seconds
Hour : Minutes
PM indicator
Day of week
Month – Day
E-5
Countdown Timer Mode Alarm Mode World Time Mode
E-4
General Guide
xPress Cto change from mode to mode.
xIn any mode, press Lto illuminate the display.
Timekeeping Mode Stopwatch Mode (ST1) Stopwatch Mode (ST2)
E-3
To view the time for another city code ................................................................ E-29
To toggle a city code time
between Standard Time and Daylight Saving Time....................................... E-30
To illuminate the display....................................................................................... E-32
To specify the illumination duration.................................................................... E-32
To turn the auto light switch on and off .............................................................. E-34
To turn the button operation tone on and off ..................................................... E-37
E-2
Procedure Lookup
The following is a handy reference list of all the operational procedures contained in
this manual.
To set the time and date ......................................................................................... E-7
To toggle the Timekeeping Mode time between DST and Standard Time ....... E-10
To toggle between 12-hour and 24-hour timekeeping ....................................... E-11
To measure times with the stopwatch
(Stopwatch Mode (ST1) and Stopwatch Mode (ST2))..................................... E-13
To use Auto-Start (ST1) ........................................................................................ E-14
To configure the countdown timer ...................................................................... E-18
To use the countdown timer................................................................................. E-20
To set an alarm time.............................................................................................. E-23
To test the alarm.................................................................................................... E-26
To turn an alarm on and off .................................................................................. E-27
To turn the Hourly Time Signal on and off.......................................................... E-28
E-1
Contents
General Guide.......................................................................................................... E-4
Timekeeping............................................................................................................. E-6
Stopwatches .......................................................................................................... E-12
Countdown Timer.................................................................................................. E-15
Alarms .................................................................................................................... E-21
World Time............................................................................................................. E-29
Illumination ............................................................................................................ E-31
Reference ............................................................................................................... E-35
Specifications ........................................................................................................ E-43
E
About This Manual
xDepending on the model of your watch, display text appears
either as dark figures on a light background or light figures
on a dark background. All sample displays in this manual are
shown using dark figures on a light background.
xButton operations are indicated using the letters shown in
the illustration.
xEach section of this manual provides you with the information
you need to perform operations in each mode. Further details
and technical information can be found in the “Reference”
section.


MA1307-EA
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#!3)/#/-054%2#/,4$

Operation Guide 3422
E-19
3. When the setting you want to change is flashing, use Band Dto change it as
described below.
Setting Screen Button Operation
Hours, Minutes Use D(+) and B(–) to change the setting.
Auto-repeat Press Dto toggle auto-repeat on ( displayed) and off
( displayed)
Progress Beeper Press Dto toggle the progress beeper on ( ) and
off ( ).
xTo specify a countdown start time of 24 hours, set .
4. Press Ato exit the setting screen.
xYou can also perform steps 1 and 2 of the above procedure whenever you need to
view the current auto-repeat and progress beeper settings.
E-18
To configure the countdown timer
1. While the countdown start time is on the display in the
Countdown Timer Mode, hold down Auntil the current
countdown start time starts to flash, which indicates the
setting screen.
xIf the countdown start time is not displayed, use the
procedure under “To use the countdown timer” (page
E-20) to display it.
2. Press Cto move the flashing in the sequence shown
below to select other settings.
Hours
Progress Beeper Auto-repeat
C
C
Minutes
C
C
E-17
Progress Beeper
When the progress beeper is turned on, the watch uses beeps to signal countdown
progress as described below.
xStarting from five minutes before the end of the countdown, the watch emits four
short beeps at the top of each countdown minute.
x30 seconds before the end of the countdown, the watch emits four short beeps.
xThe watch emits a short beep for each of the last 10 seconds of the countdown.
xIf the countdown start time is six minutes or greater, the watch emits a short beep
for each second of the final 10 seconds before the five-minute point is reached. Four
short beeps are emitted to signal when the five-minute point is reached.
E-16
Auto-repeat
When auto-repeat is turned on, the countdown restarts automatically from the
countdown start time when it reaches zero.
When auto-repeat is turned off, the countdown stops when it reaches zero and the
display shows the original countdown start time.
xPressing Dwhile an auto-repeat countdown is in progress pauses the current
countdown. You can resume the auto-repeat countdown by pressing D, or you can
press Ato reset to the countdown time starting value.
Countdown Timer Beeper Operations
The watch beeps at various times during a countdown so you can keep informed
about the countdown status without looking at the display. The following describes the
types of beeper operations the watch performs during a countdown.
Countdown End Beeper
The countdown end beeper lets you know when the countdown reaches zero.
xWhen the progress beeper is turned off, the countdown end beeper sounds for
about 10 seconds, or until you press any button to stop it.
xWhen the progress beeper is turned on, the countdown end beeper sounds for
about one second.
E-15
Countdown Timer
The countdown timer can be set within a range of one
minute to 24 hours. An alarm sounds when the countdown
reaches zero. The countdown timer also has an auto-
repeat feature and a progress beeper that signals the
progress of the countdown.
xAll of the operations in this section are performed in the
Countdown Timer Mode, which you enter by pressing
C(page E-5).
Configuring the Countdown Timer
The following are the settings you should configure before
actually using the countdown timer.
Countdown start time; Auto-repeat on/off; Progress beeper
on/off
xSee “To configure the countdown timer” (page E-18) for
information about setting up the timer.
Seconds
Hours
Minutes
E-14
About Auto-Start (Stopwatch Mode (ST1))
With Auto-Start, the watch performs a 5-second countdown, and stopwatch operation
starts automatically when the countdown reaches zero.
During the final three seconds of the countdown, a beeper sounds with each second.
To use Auto-Start (ST1)
1. While the stopwatch screen is showing all zeros in the
Stopwatch Mode, press B.
xThis displays a 5-second countdown screen.
xTo return to the all zeros screen, press Bagain.
2. Press Dto start the countdown.
xWhen the countdown reaches zero, a tone sounds and a
stopwatch timing operation starts automatically.
xPressing Dwhile the Auto-Start countdown is in
progress starts the stopwatch immediately.
E-13
To measure times with the stopwatch
(Stopwatch Mode (ST1) and Stopwatch Mode (ST2))
Elapsed Time
D D D D B
Start Stop Re-start Stop Clear
Split Time
D B B D B
Start Split
( displayed)
Split release Stop Clear
Two Finishes
D B D B B
Start Split
First runner
finishes. Display
time of first runner.
Stop
Second runner
finishes.
Split release
Display time of
second runner.
Clear
E-12
Stopwatches
Your watch has two stopwatch modes:Stopwatch Mode
(ST1) and Stopwatch Mode (ST2). Both stopwatch modes
let you measure elapsed time, split times, and two finishes.
The Stopwatch Mode (ST1) includes Auto-Start.
xA display range of the stopwatch is 999 hours,
59 minutes, 59.99 seconds.
xA stopwatch continues to run, restarting from zero after it
reaches its limit, until you stop it.
xA stopwatch measurement operation continues even if
you exit a Stopwatch Mode.
xExiting a Stopwatch Mode while a split time is frozen on
the display clears the split time and returns to elapsed
time measurement.
xAll of the operations in this section are performed in the
Stopwatch Mode (ST1) or Stopwatch Mode (ST2), which
you enter by pressing C(page E-4).
Seconds
1/100 second
Minutes
Timekeeping Mode time
*During stopwatch elapsed
time measurement, shows
the number of hours
elapsed.
E-11
To toggle between 12-hour and 24-hour timekeeping
In the Timekeeping Mode, press Dto toggle between 12-hour timekeeping and
24-hour timekeeping.
xWith the 12-hour format, the P(PM) indicator appears to the left of the hour digits for
times in the range of noon to 11:59 p.m. and no indicator appears to the left of the
hour digits for times in the range of midnight to 11:59 a.m.
xWith the 24-hour format, times are displayed in the range of 0:00 to 23:59, without
any indicator.
xThe 12-hour/24-hour timekeeping format you select in the Timekeeping Mode is
applied in all other modes.
xThe Pindicator is not displayed when the current time is displayed in other modes.
E-10
To toggle the Timekeeping Mode time between DST and Standard Time
1. In the Timekeeping Mode, hold down Auntil the
seconds start to flash, which indicates the setting
screen.
2. Press Cto display the DST setting screen.
3. Press Dto toggle between Daylight Saving Time
(displayed) and Standard Time ( displayed).
4. Press Ato exit the setting screen.
xThe DST indicator appears on the display to indicate
that Daylight Saving Time is turned on.
xNote that the Standard Time/Daylight Saving Time
setting affects only the currently displayed city code.
Other city codes are not affected.
DST indicator

Operation Guide 3422
E-29
World Time
World Time shows the current time in 48 cities (29 time
zones) around the world.
xAll of the operations in this section are performed in
the World Time Mode, which you enter by pressing C
(page E-5).
To view the time for another city code
In the World Time Mode, press Dto scroll eastwardly
through city codes.
In the World Time Mode, press Bto scroll westwardly
through city codes.
xFor full information about city codes, see the “City Code
Table” at the back of this manual.
xIf the current time for a city is wrong, check your
Timekeeping Mode time and time zone settings and
make necessary changes.
Current time and date in
the zone of the selected
city code
City code
E-28
To turn the Hourly Time Signal on and off
1. In the Alarm Mode, use Dto select the Hourly Time
Signal ( ).
2. Press Ato toggle it on and off.
xThe Hourly Time Signal on indicator ( ) is shown on
the display in all modes while this function is turned on.
Hourly time signal on
indicator
E-27
To turn an alarm on and off
1. In the Alarm Mode, use Dto select an alarm.
2. Press Ato toggle it on and off.
xTurning on an alarm ( , , , , or )
displays the alarm on indicator ( or ).
xIn all modes, the alarm on indicator is shown for alarm
that is currently turned on.
xThe alarm on indicator flashes while the alarm is
sounding.
xThe snooze alarm indicator ( ) flashes while the
snooze alarm is sounding and during the 5-minute
intervals between alarms.
Snooze alarm indicator
E-26
xPerforming any one of the following operations during a 5-minute interval between
snooze alarms cancels the current snooze alarm operation.
Displaying the Timekeeping Mode setting screen (page E-7)
Displaying the setting screen (page E-23)
To test the alarm
In the Alarm Mode, hold down Dto sound the alarm.
E-25
4. While a setting is flashing, use Dand Bto change it as described below.
Screen To do this: Do this:
Change the hour and
minutes Use D(+) and B(–).
xWith the 12-hour format, set the time correctly
as a.m. or p.m. (Pindicator).
xTo set an alarm that does not include a month
and/or day, set for each setting.
Change the month and day
5. Press Ato exit the setting screen.
Alarm Operation
The alarm tone sounds at the preset time for 20 seconds, regardless of the mode the
watch is in. In the case of the snooze alarm, the alarm operation is performed a total
of seven times, every five minutes, until you turn the alarm off (page E-27).
xAlarm and Hourly Time Signal operations are performed in accordance with the
Timekeeping Mode time.
xTo stop the alarm tone after it starts to sound, press any button.
E-24
2. After you select an alarm, hold down Auntil the hour setting of the alarm time
starts to flash, which indicates the setting screen.
xThis operation turns on the alarm automatically.
3. Press Cto move the flashing in the sequence shown below to select other
settings.
Hour Minutes Month Day
C
C
C C
E-23
To set an alarm time
1. In the Alarm Mode, use Dor Bto scroll through the
alarm screens until the one whose time you want to set
is displayed.
xTo set a one-time alarm, display an alarm screen , , , or . To
set the snooze alarm, display the screen.
xThe snooze alarm repeats every five minutes.
E-22
Alarm Types
The alarm type is determined by the settings you make, as described below.
xDaily alarm
Set the hour and minutes for the alarm time. This type of setting causes the alarm to
sound everyday at the time you set.
xDate alarm
Set the month, day, hour and minutes for the alarm time. This type of setting causes
the alarm to sound at the specific time, on the specific date you set.
x1-Month alarm
Set the month, hour and minutes for the alarm time. This type of setting causes the
alarm to sound everyday at the time you set, only during the month you set.
xMonthly alarm
Set the day, hour and minutes for the alarm time. This type of setting causes the
alarm to sound every month at the time you set, on the day you set.
E-21
Alarms
You can set up to five independent multi-function alarms
with hour, minutes, month, and day. When an alarm is
turned on, the alarm tone sounds when the alarm time is
reached. One of the alarms is a snooze alarm, while the
other four are one-time alarms.
You can also turn on an Hourly Time Signal that causes
the watch to beep twice every hour on the hour.
xThere are five alarm screens numbered , , ,
and for the one-time alarm, a snooze alarm screen
indicated by . The Hourly Time Signal screen is
indicated by .
xAll of the operations in this section are performed in the
Alarm Mode, which you enter by pressing C(page E-5).
Alarm date
(Month – Day)
Alarm time
(Hour : Minutes)
Alarm number
Alarm on indicator
E-20
To use the countdown timer
Press Dwhile in the Countdown Timer Mode to start the
countdown timer.
xThe countdown timer operation continues even if you exit
the Countdown Timer Mode.
xPress Dwhile a countdown operation is in progress to
pause it. Press Dagain to resume the countdown.
xTo stop a countdown operation completely, first pause
it (by pressing D), and then press B. This returns the
countdown time to its starting value.

Operation Guide 3422
E-39
Timekeeping
xResetting the seconds to while the current count is in the range of 30 to
59 causes the minutes to be increased by 1. In the range of 00 to 29, the seconds
are reset to without changing the minutes.
xThe year can be set in the range of 2000 to 2099.
xThe watch’s built-in full automatic calendar makes allowances for different month
lengths and leap years. Once you set the date, there should be no reason to change
it except after you have the watch’s battery replaced.
World Time
All World Time Mode times are calculated from the current Home City time in the
Timekeeping Mode using UTC time differential values.
xThe seconds count of the World Time is synchronized with the seconds count of the
Timekeeping Mode.
xThe UTC differential is a value that indicates the time difference between a
reference point in Greenwich, England and the time zone where a city is located.
E-38
Auto Return Features
xIf you leave the watch in the Alarm Mode for two or three minutes without performing
any operation, it automatically changes to the Timekeeping Mode.
xIf you leave a screen with flashing digits on the display for two or three minutes
without performing any operation, the watch automatically exits the setting screen.
Scrolling
The Band Dbuttons are used in various modes and setting screens to scroll
through data on the display. In most cases, holding down these buttons during a scroll
operation scrolls at high speed.
Initial Screens
When you enter the World Time or Alarm Mode, the data you were viewing when you
last exited the mode appears first.
E-37
Button Operation Tone
The button operation tone sounds any time you press one
of the watch’s buttons. You can turn the button operation
tone on or off as desired.
xEven if you turn off the button operation tone, the alarms,
the Hourly Time Signal, the countdown alarm, and
stopwatch auto start all operate normally.
To turn the button operation tone on and off
In any mode (except when a setting screen is on the
display), hold down Cto toggle the button operation tone
on ( not displayed) and off ( displayed).
xHolding down Cto turn the button operation tone on or off also causes the watch’s
current mode to change.
xThe mute indicator is displayed in all modes when the button operation tone is
turned off.
Mute indicator
E-36
xThe following table shows the information that appears in graphic area A.
Mode Graphic Area A
Timekeeping Timekeeping Mode seconds
World Time Timekeeping Mode seconds
Stopwatch (ST1 and ST2) Sweeps from left to right
Countdown Timer Sweeps from right to left
Alarm No indication
xIn all modes, graphic area B shows the Stopwatch Mode (ST1) minutes (one
segment each for 5 minutes, 10 minutes, etc.).
xIn all modes, graphic area C shows the Stopwatch Mode (ST2) minutes (one
segment each for 5 minutes, 10 minutes, etc.).
E-35
Reference
This section contains more detailed and technical information about watch operation.
It also contains important precautions and notes about the various features and
functions of this watch.
Graphic Areas
There are three graphic areas named A, B, and C. The information shown in each
graphic area depends on the current mode.
Graphic area B
Graphic area C
Graphic area A
E-34
Warning!
xAlways make sure you are in a safe place whenever you are reading the watch
using the auto light switch. Be especially careful when running or engaged
in any other activity that can result in accident or injury. Also take care that
sudden illumination by the auto light switch does not startle or distract others
around you.
xWhen you are wearing the watch, make sure that its auto light switch is turned
off before riding on a bicycle or operating a motorcycle or any other motor
vehicle. Sudden and unintended operation of the auto light switch can create a
distraction, which can result in a traffic accident and serious personal injury.
To turn the auto light switch on and off
In the Timekeeping Mode, hold down Bfor about three seconds to toggle the auto
light switch on (auto light switch indicator displayed) or off (auto light switch indicator
not displayed).
xThe auto light switch indicator is on the display in all modes while the auto light
switch is turned on.
xIn order to protect against running down the battery, the auto light switch turns off
automatically approximately six hours after you turn it on.
E-33
About the Auto Light Switch
While the auto light switch is enabled, illumination turns on whenever you position
your wrist as described below in any mode.
Moving the watch to a position that is parallel to the ground and then tilting it
towards you at more than 40 degrees causes illumination to turn on.
xWear the watch on the outside of your wrist.
Parallel to ground More than 40°
E-32
To illuminate the display
In any mode, press Lto turn on illumination.
xThe above operation turns on illumination regardless of the current auto light switch
setting.
xYou can use the procedure below to select either 3 seconds or 5 seconds as the
illumination duration. When you press L, the illumination will remain on for about
3 seconds or 5 seconds, depending on the current illumination duration setting.
To specify the illumination duration
1. In the Timekeeping Mode, hold down Auntil the
seconds start to flash, which indicates the setting
screen.
2. While the seconds are flashing, press Bto toggle the
setting between 3 seconds ( ) and 5 seconds ( ).
3. Press Ato exit the setting screen.
E-31
Illumination
This watch has an LED (light-emitting diode) that cause
the entire display to glow for easy reading in the dark. The
watch’s auto light switch turns on illumination automatically
when you angle the watch for reading towards your face.
xThe auto light switch must be turned on (indicated by the
auto light switch indicator) for it to operate.
xSee “Illumination Precautions” (page E-40) for more
important information.
Auto light switch indicator
E-30
To toggle a city code time between Standard Time and Daylight Saving Time
1. In the World Time Mode, use D(east) and B(west) to
display the city code (time zone) whose Standard Time/
Daylight Saving Time setting you want to change.
2. Hold down Afor about one second to toggle Daylight
Saving Time (DST displayed) and Standard Time (DST
not displayed).
xThe DST indicator is on the display whenever you display
a city code for which Daylight Saving Time is turned on.
xNote that the DST/Standard Time setting affects only
the currently displayed city code. Other city codes are
not affected.
DST indicator

Operation Guide 3422
L-4
*In December 2007, Venezuela changed its offset from –4 to –4.5. Note,
however, that this watch displays an offset of –4 (the old offset) for the CCS
(Caracas, Venezuela) city code.
** The above is current as of December 2012. This watch does not reflect the
change in the Moscow (MOW) time offset to +4. Because of this, you should
leave the summer time setting turned on (which advances the time by one hour)
for Moscow (MOW).
xThis table shows the city codes of this watch.
xThe rules governing global times (UTC offset and GMT differential) and summer
time are determined by each individual country.
L-3
City
Code City
UTC Offset/
GMT Differential
THR Tehran +3.5
DXB Dubai +4
KBL Kabul +4.5
KHI Karachi +5
DEL Delhi +5.5
DAC Dhaka +6
RGN Yangon +6.5
BKK Bangkok +7
SIN Singapore
+8
HKG Hong Kong
BJS Beijing
PER Perth
SEL Seoul +9
TYO Tokyo
ADL Adelaide +9.5
City
Code City
UTC Offset/
GMT Differential
SYD Sydney +10
NOU Noumea +11
WLG Wellington +12
L-2
City Code Table
City
Code City
UTC Offset/
GMT Differential
PPG Pago Pago –11
HNL Honolulu –10
ANC Anchorage –9
LAX Los Angeles –8
DEN Denver –7
MEX Mexico City –6
CHI Chicago
NYC New York –5
CCS* Caracas –4
YYT St. Johns –3.5
RIO Rio De Janeiro –3
BUE Buenos Aires
RAI Praia –1
LON London 0
DKR Dakar
City
Code City
UTC Offset/
GMT Differential
MAD Madrid
+1
PAR Paris
MCM Monte Carlo
ROM Rome
BER Berlin
STO Stockholm
ATH Athens
+2
JNB Johannesburg
ANK Ankara
NIC Nicosia
HEL Helsinki
CAI Cairo
JRS Jerusalem
MOW** Moscow +3
JED Jeddah
L-1
City Code Table
E-44
Countdown Timer
Measuring unit: 1 second
Input range: 1 minute to 24 hours (1-minute increments and 1-hour increments)
Other: Auto-repeat timing; Progress beeper
Alarms: 5 multi-function* alarms (four one-time alarms; one snooze alarm);
Hourly Time Signal
*Alarm type: Daily alarm, date alarm, 1-month alarm, monthly alarm
World Time: 48 cities (29 time zones)
Other: Daylight Saving Time/Standard Time
Illumination: LED (light-emitting diode); Selectable illumination duration;
Auto Light Switch
Other: Button operation tone on/off
Battery: One lithium battery (Type: CR2016)
Approximately 2 years on type CR2016 (assuming alarm operation 20 seconds per
day and one illumination operation 3 seconds per day)
E-43
Specifications
Accuracy at normal temperature: ±15 seconds a month
Timekeeping: Hour, minutes, seconds, p.m. (P), month, day, day of the week
Time format: 12-hour and 24-hour
Calendar system: Full Auto-calendar pre-programmed from the year 2000 to 2099
Other: Home Time zone (selectable in 0.5-hour increments in the range of –12.0 to
+14.0); Daylight Saving Time (summer time)/Standard Time
Stopwatch (ST1)
Measuring unit: 1/100 second
Measuring capacity: 999:59' 59.99''
Measuring modes: Elapsed time, split time, two finishes
Other: Auto-Start
Stopwatch (ST2)
Measuring unit: 1/100 second
Measuring capacity: 999:59' 59.99''
Measuring modes: Elapsed time, split time, two finishes
E-42
xUnder certain conditions, illumination may not turn on until about one second after
you turn the face of the watch towards you. This does not necessarily indicate
malfunction of the auto light switch.
xYou may notice a very faint clicking sound coming from the watch when it is shaken
back and forth. This sound is caused by mechanical operation of the auto light
switch, and does not indicate a problem with the watch.
E-41
Auto light switch precautions
xAvoid wearing the watch on the inside of your wrist. Doing so causes the auto light
switch to operate when it is not needed, which shortens battery life. If you want to
wear the watch on the inside of your wrist, turn off the auto light switch feature.
xIllumination may not turn on if the face of the watch is more
than 15 degrees above or below parallel. Make sure that the
back of your hand is parallel to the ground.
xIllumination turns off after the preset illumination duration (see
“To specify the illumination duration” (page E-32)), even if you
keep the watch pointed towards your face.
xStatic electricity or magnetic force can interfere with proper
operation of the auto light switch. If illumination does not turn
on, try moving the watch back to the starting position (parallel
with the ground) and then tilt it back towards you again. If this
does not work, drop your arm all the way down so it hangs at
your side, and then bring it back up again.
E-40
xThe letters “UTC” is the abbreviation for “Coordinated Universal Time”, which is the
world-wide scientific standard of timekeeping. It is based upon carefully maintained
atomic (cesium) clocks that keep time accurately to within microseconds. Leap
seconds are added or subtracted as necessary to keep UTC in sync with the Earth’s
rotation.
Illumination Precautions
xIllumination loses power after very long use.
xIllumination may be hard to see when viewed under direct sunlight.
xIllumination turns off automatically whenever an alarm sounds.
xFrequent use of illumination runs down the battery.