Fujitsu CD5425 Owner's Manual page 94

How to operate the tuner with an optional HD Radio tuner connected (U.S.A. only)
Turn the [SEL] button to select AUTO or OFF.
In the [AUTO] setting, the selection is switched between digital and
analog reception automatically. In areas where digital reception is
not possible, reception is automatically switched to analog to avoid
loss of reception.
During digital reception, [DIGITAL] is shown on the display. This is
cleared during analog reception.
In the [OFF] setting, reception is always analog.
Press the [SEL] button.
The selected setting will take effect.
Press the [RTN] button.
At this time, other adjustments can also be made in function mode.
Press the [FUNC] or [RTN] button to exit function mode.
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