Casio 4390 Manual page 24

Time Calibration Signal Reception
There are two different methods you can use to receive the time calibration signal:
auto receive and manual receive.
• Auto Receive
With auto receive, the watch receives the time calibration signal automatically up to six
times a day (five times for the China signal). When any auto receive is successful, the
remaining auto receive operations are not performed. For more information, see
"About Auto Receive" (page E-25).
• Manual Receive
Manual receive lets you start a time calibration receive operation with the press of a
button. For more information, see "To perform manual receive" (page E-28).
E-22