Apple Macintosh PowerBook 180 computers - Manual (Page 260)

Using sound input and output devices
Built-in microphone
Your computer has a built-in microphone centered just below the
display. The microphone has no on/off switch; it is controlled by
the program you use to record sounds. (Sound recording is
described in the chapter on sound and color.)
External microphone
In addition to its internal microphone, your PowerBook has a
sound input port (marked with this icon:
X ) to which you can
connect an external microphone.
You cannot use both internal and external microphones at the
same time. If an external microphone is connected, the internal
microphone does not work.
s Warning: Do not plug a sound output device (such as a pair
of headphones) into the sound input port. Doing so may
damage your audio equipment.
s
244 Chapter 14: Expanding Your Computer System
Microphone