Casio 2581 User manual

1
USER’S GUIDE 2581/2671
What is a radio-controlled watch?
Your radio-controlled watch is designed to receive a time
calibration signal that contains standard time data and adjust its
current time setting accordingly.
Signal data
Transmitter Long-wave time
calibration signal
Inside the watch
Decoding
Watch
Time data
Signal received using
built-in antenna.
Watch decodes
received data
and converts it
to time data.
Time is
adjusted
according to
time data.
Cesium
atomic clock
After the watch receives the Standard Time signal, it
performs internal calculations to determine the current time.
Because of this, there may be an error of up to one second
in the displayed time.
Calibration Signal
The Japanese calibration signal (Call Sign: JJY) is maintained by
the independent Japan Ministry of Posts and Telecommunications
Communication Research Laboratory (CRL). It is a long wave
signal transmitted 24 hours a day from the Mt. Otakadoya
transmitter (40kHz) located in Tamura-gun, Fukushima Prefecture,
and from the Mt. Hagane transmitter (60kHz) located on the
border between Saga Prefecture and Fukuoka Prefecture.
The U.S. calibration signal (Call Sign: WWVB) is transmitted by
the National Institute of Standards and technology from Fort
Collins, Colorado.
Though the calibration signal is normally transmitted 24 hours
a day, transmission may be interrupted occasionally due to
maintenance, lightening, etc.
How a Radio-controlled Watch Works Reception Range
This watch is designed to receive the standard time calibration signal of Japan (JJY) or of the United States (WWVB). The signal that is
received depends on the current Home City setting.
When this Home City is selected: You can receive this signal
Either the Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal (60kHz)
Fort Collins, Colorado signal
1000km
Mt. Hagane
(60kHz)
Mt. Otakadoya
(40kHz)
500km
1000km
500km
Transmitter Locations
Under optimum conditions, the calibration signal should be
receivable up to 1,000 kilometers from the transmitter. Note
that the wave is relatively weak at distances greater than
500km, so reception may be poor at long distances.
Location
Reception is difficult and may even be impossible in the locations
described below. Avoid such locations when performing signal
reception.
You should think of your watch operating like a radio or TV when it
is receiving the calibration signal.
If you are experiencing problems with reception, move away from
the types of locations described above to a location with better
reception, and try again.
Receiving the Calibration Signal
There are two methods you can use to receive the time calibration
signal.
Auto reception (Reception is performed automatically at 2:00,
4:00, and 6:00 each morning.)
Manual reception (You initiate reception using a button
operation.)
The watch is set up for auto reception at the factory, so all you
need to do is to place it in a location that allows good reception
each night.
Setting Up to Make Reception Easier
Remove the watch from your wrist and place it somewhere so its top
(12 o’clock side, where the antenna is located) is facing
approximately in the direction of the signal transmitter. Keep the
watch away from metal objects.
Resin band
Metal band
Orienting the watch so it is sideways to the transmitter makes it
more difficult to receive the signal.
Do not move the watch while it is receiving the calibration signal.
Time Required for Reception
Signal reception takes anywhere from about two to six minutes.
Note that when “A/T” (auto) is specified as the transmitter
selection mode, signal reception can take up to 12 minutes.
*See “Specifying the Transmitter Selection Mode in Japan” for
more information.
Triggering Reception Manually
In the Timekeeping Mode:
Hold down the BB
BB
Bbutton for
about two seconds.
The watch beeps and reception
starts. Ongoing reception is
indicated by the icon and the
receive indicator. See “Receive Icon
and Indicator” for more information.
 To interrupt reception
Press the BB
BB
Bbutton.
All other buttons besides Bare disabled during signal reception.
 When reception is successful
The watch adjusts its current time setting, and then beeps and
displays the time and date of the adjustment.
The icon and the receive indicator remain on the display to
indicate that reception was successful.
 When reception fails
The watch does not adjust its current time setting, and displays
“ERR” instead.
The display also return to the normal timekeeping screen
automatically if you do not perform any operation for about one
or two minutes.
Receive Icon and Indicator
While reception is in progress, the
icon and the receive indicator
cycle from “Unstable” through
“Stable” as shown below. How far
they cycle depends on the signal
strength. Keep the watch in a
location where reception is stable
while reception is in progress.
Unstable Stable
Even under optimum reception conditions, it takes at least
10 seconds before reception starts.
Use the receive icon and receive indicator to check
reception status and to determine the best location for
signal reception.
Note that weather, the time of day, surroundings, and other
factors can all affect reception.
Receive icon
Receive indicator
Near high-voltage linesAmong or near buildings
Next to a household
appliance or office equipment
(TV, speaker, fax, PC, etc.)
Inside a vehicle
(automobile, train, plane, etc.)
Near mountains
In a location where there is
radio interference
(construction site, airport, etc.)
Fort Collins
3000km
1000km
Transmitter Location
Under optimum conditions, the calibration signal should be
receivable up to 3,000 kilometers from the transmitter. Note
that the wave is relatively weak at distances greater than
1,000km, so reception may be poor at long distances.
Geographic contours, nearby buildings, the season, and the time of day can make reception impossible even when you are within range of
the transmitter.
Best reception is possible late at night.
MA0302-A
The following explanation covers the radio-controlled timekeeping function only.
For other functions, go to the download page for Module 2578,
which is the export model that has the same functions, except for radio-controlled timekeeping.

2
USER’S GUIDE 2581/2671
Turning Auto Reception On and Off
1. Display the setting screen.
In the Timekeeping Mode:
Use the AA
AA
Abutton to
display the “ ”
indicator, and then press
the BB
BB
Bbutton.
This causes the current setting
(On or OF) to appear on the
display.
2. Turn auto reception on or off.
Press CC
CC
Cor AA
AA
Ato toggle
the auto reception setting
on (On) and off (OF).
Viewing the Last Reception Date and Time
In the Timekeeping Mode:
Press the BB
BB
Bbutton.
This displays the date and time that signal reception was
complete and the current time and date were adjusted.
The month and day screen and hour and minute screen alternate
at two-second intervals.
To return to the timekeeping screen, press the Bbutton again.
The display also returns to the normal timekeeping screen
automatically if you do not perform any operation for about one or
two minutes.
2-second
interval
Home Time
(24-hour format)
Reception date and time
Important!
The calibration signals received by this watch include two data
groups: an hour-minute-second group and a year-month-day group.
The icon will remain on the display only if the hour-minute-
second group and year-month-day group are both received. It will
not remain on the display if only the hour-minute-second group is
received.
Toggle Toggle
Specifying the Transmitter
Selection Mode in Japan
When Tokyo (TYO) is selected as the Home City, you can select
either of two different transmitters for reception.
The initial factory default settings of the watch are TYO (Tokyo) for
the Home City, and A/T (auto) for the transmitter selection mode.
1. Display the setting screen.
In the Timekeeping Mode:
Use the AA
AA
Abutton to
display the “ ”
indicator, and then press
the BB
BB
Bbutton.
This causes the current auto
reception setting (On or OF) to
appear on the display.
2. Display the transmitter selection mode setting screen.
Press the BB
BB
Bbutton.
3. Exit the setting screen.
Press the BB
BB
Bbutton 11 times.
This exits the setting screen can causes “ ” to appear
on the display. To return to the timekeeping screen, press the
Cbutton once (or the Abutton six times).
The display also will return to the normal timekeeping screen
automatically if you do not perform any operation for about
two or three minutes.
Calibration Signal Reception
Precautions
Auto reception can be performed while the watch is in the
Timekeeping Mode or World Time Mode only.
Operating any button while auto reception is in progress will cause
the watch to beep and then exit the receive operation.
Make sure you are within the range of the calibration signal
transmitter before performing the receive operation. Remember
that geographic contours, nearby buildings, the season, and the
time of day can make reception impossible even when you are
within range of the transmitter.
Proper reception may be impossible if there is something blocking
the signal. If reception is unsuccessful, try again.
This watch is designed to adjust its current time setting in
accordance with the calibration signals transmitted in Japan and
the United States only. Note that you will need to make your own
adjustments when using this watch outside of Japan or the United
States, or in any area that is outside the range of one of the
receivable time calibration signal transmitters.
When the watch is unable to adjust its time signal using the
calibration signal for some reason, timekeeping accuracy is within
±15 seconds per month.
Strong electrostatic charge can cause timekeeping error.
Signal reception is cancelled if an alarm starts to sound while it is
being performed.
The watch’s calendar shows dates up to the year 2039. Attempting
a receive operation after that causes an error.
3. Select the transmitter selection mode you want.
Use CC
CC
Cand AA
AA
Acycle
through the settings until
the one you want is
displayed.
* A/T
With this setting, the watch automatically selects either the
Mt. Otakadoya signal (40kHz) or the Mt. Hagane signal
(60kHz), whichever is strongest.
* The frequency first used by the watch is the one that was
last successful.
* JPN 40
With this setting, the watch always receives the Mt.
Otakadoya signal (40kHz).
* JPN 60
With this setting, the watch always receives the Mt. Hagane
signal (60kHz).
4. Exit the setting screen.
Press the BB
BB
Bbutton 10 times.
This exits the setting screen can causes “ ” to appear
on the display. To return to the timekeeping screen, press the
Cbutton once (or the Abutton six times).
The display also will return to the normal timekeeping screen
automatically if you do not perform any operation for about
two or three minutes.
(Back) (Forward)
Troubleshooting
Cannot perform manual reception.
Possible Cause: The watch is not in the Timekeeping
Mode or World Time Mode.
The Home City is set to a city other than
TYO (Tokyo), NYC (New York), CHI
(Chicago), DEN (Denver), or LAX (Los
Angeles).
Corrective Measures: Perform manual reception while a time
screen is on the display in the Timekeeping
Mode or World Time Mode only.
Change Home City To TYO (Tokyo), NYC
(New York), CHI (Chicago), DEN
(Denver), or LAX (Los Angeles).
The icon is not displayed even though auto reception is
turned on.
Possible Cause: A single receive operation was not
successful.
Both the hour-minute-second group and
year-month-day group were not received.
The watch is not in the Timekeeping
Mode or World Time Mode when an auto
reception time is reached.
You performed manual reception, which
clears the icon from the display.
Corrective Measures: Check to make sure the watch is in a
location where it can receive the signal.
Place the watch in a location where
reception conditions are good.
Make sure that the watch is in the
Timekeeping Mode or World Time Mode
during the auto reception times.
The icon disappears from the display
whenever you change the current time
setting manually.
displayed
not displayed
If only the hour-minute-second group is received, the Timekeeping
Mode date at the time of reception is recorded as the last reception
date.
Hour-minute-second group and year-
month-day group received
Hour-minute-second group only received
Time setting is incorrect following signal reception.
Possible Cause: Summer time is turned on or the wrong
Home City is selected.
Corrective Measures: Turn off summer time so the DST
indicator is not on the display.
Configure the watch for the correct DST
setting and Home City setting.
If you cannot receive the calibration signal or if the current time
setting is incorrect after signal reception, check the current setup
of the watch. The following are the watch’s factory default settings,
which are configured automatically whenever you have the battery
of the watch replaced.
Auto Receipt
Transmitter
Home City
Summer Time
On
Auto Japan transmitter select
(40kHz/ 60kHz)
Tok y o
Auto (according to signal data)
The following explanation covers the radio-controlled timekeeping function only.
For other functions, go to the download page for Module 2578,
which is the export model that has the same functions, except for radio-controlled timekeeping.