The S100 has a built-in speaker that is loud enough for group listening in a quiet room as well as a 3.5 mm earphone socket for private listening. It is powered by a pair of AA batteries and can achieve well over 200 hours of playing time from a pair of good alkaline batteries. It can also use rechargeable NiMH batteries, which could be useful in remote situations where disposable batteries are not readily available. In such cases NiMH batteries with a solar charger would serve very well.
The button functions are as follows:
The S100 uses CELP for speech compression and stores the audio data on an SLC NAND flash chip that is soldered directly onto the printed circuit board.