4 Channels Microphone and 2 line input, treble and bass can be controlled separately . * 6 Channels Partition output, and partition volume independent control. * Built in bell. Bell tone optional: 4 tones and 2 tones (built-in), alarm generator. * Mp3 decoding module supports usb / sd / bluetooth / fm radio playback function. With the MP3 remote control, support power off memory function, MIC recording function. * When the alarm generator starts, background music will be closed and6 partition output will automatically open to maximum output volume. * Built in 24V DC power input.