Sony ICF-SC1PC - Manual (Page 8)

Using the earphone
To listen through the earphone, plug in the earphone to
the jack as shown in the illustration.
-NOTICE
Be sure to adjust VOL (volume) to a moderate
level before turning on the power or plugging in
the earphone. There will be no sound when there
is no reception (squelch closed). Sudden
reception (opening of the squelch) may cause
unexpected loud sound and may cause hearing
damage.
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