Function explanation accessible by moving mouse on buttons
POWER ON OFF
Turn the unit ON and OFF. For safety, always turn off when stop using. DVD/ USB
To switch DISC or USB playback in stop mode. Press OK to confirm. See instruction of DVD/USB button on remote. L/R
To select audio playback modes (mono left, mono right and STEREO) Vocal Cancel
This button combines VOCAL CANCEL (cancel guide vocal of multiplex media) and VOCAL PARTNER (weaken guide vocal of multiplex media when you sing to the microphone) functions. 
O/I: Press VOCAL CANCEL button successively to switch among VOCAL CANCEL RIGHT, VOCAL CANCEL LEFT, VOCAL PARTNER RIGHT, VOCAL PARTNER LEFT and NO VACAL. MENU
Show up the menu when playing a DVD AUDIO
To switch different audio outputs of DVD disc. KEY CONTROL
To adjust total 14 steps key level of music in Karaoke mode. Auto reset after each song finishes.
Note: Only works under Karaoke Mode. Tray door. 
SOS:
Open tray door, press 222888, then press STOP button, the machine will be reset to factory default in case of any uncorrectable operation. NUMERIC BUTTONS
Direct numeric access buttons are applicable for tracks up to 2048 CD+G Program
To program playing order of tracks. Only work on CD+G and CD disc.
O/I:
1.Press STOP to stop playing.
2.Press PROGRAM to enter program screen.
3.Select the track to play by pressing numeric keys. The number of track shows on screen.
4.Press OK to confirm the selection. Programmed number of track is added automatically. Repeat step 3 and 4 for more tracks programming.
5.Press PLAY button to play tracks programmed. NEXT
To skip to the next track. STOP
To stop disc playback. PLAY/PAUSE
To play or pause disc playback. EJECT
To open and close the tray door Display window
To show graphical information on the operating status. ECHO
To raise or lower the echo level of microphones. Mid level is recommended. Mic 2 VOL
To raise or lower the volume of MIC 2 Mic 1 VOL
To raise or lower the volume of MIC 1 PREVIOUS
To skip to the previous track. USB port
To connect the flash drive and hard drive. See manual for supporting files. Note: Not for recording. Mic 1 
1/4¡± microphone jack mic 2
1/4¡± microphone jack