Compaq 1610 Reference Manual page 61

The Voice Memo application allows you to record, play, and
manage voice messages much like you would manage data files
in Windows CE Explorer.
When a voice message is recorded, your handheld PC
automatically saves it in .WAV format. However, you can choose
to save your messages in other formats as well. The following
table provides a brief description of the voice memo file formats
and features.
.VSELP
.GSM
.WAV
To select a format before recording, tap Tools from the Voice
Memo toolbar, then select Wav, Vselp, or Gsm.
To convert a previously recorded memo to another format, select
Tools Convert. Then select Wav, Vselp, or Gsm.
Conversions that are not available for the selected memo
are grayed out.
Lower
Medium
Higher
Smaller
Medium
Larger