The Sharp SPC900 clock has a radio-controlled function that automatically synchronizes the time from an atomic clock in Fort Collins, Colorado. However, if it is not possible to synchronize with the atomic clock, the time can also be set manually using the Time, Up and Down buttons.
One can setup the transmitter on the Sharp SPC900 clock by inserting two AA batteries, pressing the Reset button, pressing the Channel button on the back of the clock and replacing the battery door. The clock synchronizes with the time reported by the atomic clock in Fort Collins.
When the Sharp SPC900 is not able to receive a signal from the atomic clock, it is possible to temporarily set the clock's time manually. To do so, one should press and hold the Time button on the back of the clock until the year digits appear, then use the Up and Down buttons to change its values. Then press the Time button again to move to the month digits. Repeat the process to set the date, hour, minute and second. Note that when a transmitter signal is available, the clock resynchronizes with the exact time reported by the atomic clock in Colorado.
The time zone can also be configured by pressing the Time button once to go to alarm time mode, then press the Up button to move between different time zones, then press the Time button to save the setting.