Compaq 1610 Reference Manual page 20

Battery charge
light (amber)
Alarm light
(green)
Speaker
Microphone
Infrared (IR) port
Turns on when the optional
rechargeable NiMH battery pack is
being recharged; also turns on when
the device is connected to external
power
Turns off when charging is complete.
Blinks once when the device is turned
on.
Blinks continuously when an alarm
you have set goes off.
Turns off when you press the alarm
button or stop the alarm through the
software.
Produces sound for the alarm, playback of
voice memos, and other audio effects. For
information on setting the speaker level,
see "Controlling Volume" in Chapter 8.
Speak into the microphone while pressing
the record button to record a voice memo.
Works whether device is open or closed.
Allows for wireless infrared
communication.