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@@ -87,7 +87,7 @@ The lower nibble (bits 0 to 3) of the status can be modified from the applicatio
 
 ## Sound output
 
-ESOP supports monophonic sound output with a beeper controllable via `06` port. As long as the port value is non-zero, the beeper must emit a sound wave of the specified frequency. The frequency is specified in semitones relative to A4 (440 Hz), with A4 itself being located at `30` value.
+ESOP supports monophonic sound output with a beeper controllable via `06` port. As long as the port value is non-zero, the beeper must emit a sound wave of the specified frequency. The frequency is specified in semitones relative to A4 (440 Hz), with A4 itself being located at the value `30`. Setting the port value to `00` must halt the sound output.
 
 ## System calls