CASIO PRT71-1AV
Owner's Manual

2307/2335/2355/2357-2
ABOUT THE BACKLIGHT
This watch features an electroluminescent (EL) backlight that helps you easily read the face, even in total darkness. Its Auto Backlight function automatically lights the watch face whenever you turn your wrist towards your face. � Static electricity or magnetic force can interfere with proper operation of the auto backlight function. If the auto backlight does not illuminate, 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. � Under certain conditions the backlight may not light until about one second or less after turn the face of the watch towards you. This does not necessarily indicate malfunction of the backlight.

M

A

B

� For Module 2307 and 2357, the backlight illuminates both the digital display and analog face. For Module 2335 and 2355, the backlight illuminates the digital display only.

Warning!
� Never try to read your watch when mountain climbing or hiking in areas that are dark or in areas with poor footing. Doing so is dangerous and can result in serious personal injury. � Never try to read your watch when running where there is the danger of accidents, especially in locations where there might be vehicular or pedestrian traffic. Doing so is dangerous and can result in serious personal injury. � Never try to read your watch when riding on a bicycle or when operating a motorcycle or any other motor vehicle. Doing so is dangerous and can result in a traffic accident and serious personal injury. � When you are wearing the watch, make sure that its auto backlight function is turned off before riding on a bicycle or operating a motorcycle or any other motor vehicle. Sudden and unintended operation of the auto backlight can create a distraction, which can result in a traffic accident and serious personal injury.

C

10 08

D

Note � The backlight of the watch employs an electroluminescent (EL) light, which loses illuminating power after very long use. � Frequent use of the backlight shortens the battery life. � The illumination provided by the backlight may be hard to see when viewed under direct sunlight. � The watch will emit an audible sound whenever the display is illuminated. It does not indicate malfunction of the watch. � The backlight automatically turns off whenever an alarm sounds.

To manually turn on the backlight
� Pressing B in any mode besides the Countdown Alarm Mode or Stopwatch Mode illuminates the display for about 1.5 second. The backlight is disabled while a setting screen is on the display.

To switch the auto backlight function on and off
While in the Timekeeping Mode, hold down D for one second to turn the Auto Backlight function on and off.

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BAROMETER MODE
This watch uses a pressure sensor to measure barometric pressure. It can be adjusted to correct for measurement error.

Hold down D.

10 8 88 8 08
Auto backlight indicator

D

10 8 88 8 08

D

Important ! The barometer that is built into this watch measures changes in barometric pressure, which you can then apply to your own weather predictions. It is not intended for use as a precision instrument in official weather prediction or reporting applications.

ON

OFF

on. Repeat the above procedure to turn the auto backlight function back on if you want. � Pressing B in any mode besides the Countdown Alarm Mode or Stopwatch Mode illuminates the display for about 1.5 second, regardless of the auto backlight function on/off setting.

About barometric pressure measurements
The watch takes barometric pressure measurements every five seconds for the first two minutes after you enter the Barometer Mode. The Barometer Mode indicator 1 flashes on the display during these two minutes. After the first two minutes, the Barometer Mode indicator 1 stops flashing, and the watch automatically takes measurements every two hours (starting from midnight). The watch continues to take barometric pressure readings every two hours, even if you change to another mode. Measurement data can be viewed on the Timekeeping Mode screen on the barometric pressure graph.
Last measurement *2 (updated every two hours) Barometer Mode indicator 1
A B

About the Auto Backlight function
While the Auto Backlight function is turned on, the backlight automatically lights for about 1.5 second in any mode whenever you position your wrist as described below. Important! Avoid wearing the watch on the inside of your wrist. Doing so causes the Auto Backlight to operate when it is not needed, which shortens battery life. Moving the watch to a position that is parallel to the ground and then tilting it towards you more than 40 degrees causes the backlight to illuminate.

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� The auto backlight indicator is shown on the display in all modes while the auto backlight function is on. � In order to protect against running down the battery, the auto backlight function is automatically turned off approximately six hours after you turn it

Example barometer applications
� Before going mountain climbing, you can take readings to predict upcoming weather. � You can predict the weather for golf or other outdoor activities.

5 seconds later

Unit of measurement

10 13
8A A0

Parallel to ground

More than 40°

C

D

M
10 13

Remaining memory Barometer Mode indicator 2

Barometric pressure graph *1

� The backlight may not illuminate if the face of the watch is more than 15 degrees off parallel as shown below. Make sure that the back of your hand is parallel to the ground.

Parallel to ground

More than 15 degrees too high

More than 15 degrees too low

*1 The barometric pressure graph shows the barometric pressure readings for the past 18 hours. The flashing point on the right of the display is the point of the last measurement. *2 The displays show �� � � � hPa� (or inHg) if a measured value falls outside the range of 460 hPa/mb to 1100 hPa/mb (13.55 inHg to 32.45 inHg). The normal display will return as soon as the pressure returns with the allowable range.

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Press A.