... 5mm stereo jack7. Audio Source: TF card,PC,MP3,MP4,MD,CD,DVD player, Mobile phone,etc 8. Switch available, volume ... of the 3.5 audio jack is to connect the PC s audio in jack,the other is to connect ... the PC s usb jack,when charging,the light is red, ... small and is used to furnish audio frequency for PC,music mobile phnone,Mp3,Mp4,CD,palm players and other portable ...