Introduction:Car MP3 Interface (CMI) is an digital virtual CD changer ， which can be easily installed and used. It is deliver CD quality music directly into car stereo system via CD changer port. CMI support direct controls from car radio panel and steering wheel. It support SD/SHSD/MMC card and Usb stick play via build-in USB slot and SD card slot. Aux port support universal aux audio line in.Car Compatible with:VW1999-2008 Beetle1998-2001 Cabrio1998-2002 Golf/GTI/R321999-2002 Jetta1999-2001 Passat1999-2004 Polo1999-2002 T51998-2001 SharanRadio Compatible with:Alpha 5， Beta 5，Gamma 5，New Beetle Alpha 5， Gamma， New Beetle Gamma CD， Monsoon， Phaeton Rhapsody， Premium 4 Clarion， Premium 5 Delco， RNS-MCD，Z6Z9(Phaeton)， Z9Z7(New Beetle)， MFD NaviFeatures:1.Direct Connection via CD changer Port with CD quality sound2. Control music files from your car radio panel or steering wheel.3.Support USB Flash， SD Card and 3.5mm jack input.4.Building in high quality MP3/WMA decoder5.Building in Amplifier chips6.No signal interfere， No battery required7.Smart design and Easy to install and useWork Theory:1. Turn off car engine and remove key from ignition2. Remove car radio from the dash in order to get assess to the back of radio3. Find CD Changer port and plug Car Mp3 Interface cable connector into it， make sure firm connection.4. Plug USB stick or SD card into Car Mp3 Interface. Turn on radio and press CD (Disc/model/CDC/AUX) button until "CD-X-X" appear on radio screen. And play music to check left and right sound. And test if can control radio track +/-，Disk +/-.5. After all test are ok， assembly radio and put Car MP3 Interface in the proper place.Product Include:1 x CMI box1 x Aux extension cable1 x Manual