Charm Sonic Transmitter Connected to 3.5mm Audio Devices, Paired with Bluetooth Devices. Stereo TransmissionBlack Transforms with bluetooth device (e.g. computer, MP3 player, PSP) with 3.5mm audio-out jack into a Bluetooth-capable music streaming solution with no additional drivers required. Supported Bluetooth profiles: A2DP. This transmitter can connect the device automatically ,you no need do anything ,just need press the on and off button until there is blue and red lights lternating flicker then it is can connect. and don't try to connect your mobile phone ,because this transmitter it is connect the earphone ,speaker . Bluetooth-capable music streaming solution with no additional drivers required. Bluetooth receiver: Pair it with your bluetooth-enabled phone, and connect it with your headset or speaker (without bluetooth function),when it show BYL-918,you just put in 0000 will be ok.