The POWER module is the most simple base of an AE modular system (alternatively to the MASTER module which adds MIDI capability). It contains

• the voltage regulation (5V) for the power supply of the modules
• two In/out-sockets (3.5mm minijack) for audio out; one of them can be used as headphone output
• a mono headphone amplifier

The power supply is a 9V DC adapter (see here); it can be connected either at the side or on the top of the module.