 to connect directly to an external audio source with an audio adapter cable. You'll need to replace the Sonet battery pack cover with the Sonet FM battery pack cover. Remove the standard battery pack cover. Make sure that the battery pack cover lock is in the unlocked position. If it is not in the unlocked position, use the screwdriver provided with your Sonet kit to turn it counter-clockwise into the unlocked position. Be careful not to use too much force. Slide the FM battery pack cover over the battery pack frame and be careful not to use excessive force. The air inlets of the battery pack cover should be on the same side as the coil cable socket of the control unit. Insert the 3-pin plug of the audio adapter cable into the FM port and the 3.5 mm plug into the headphone port of the audio device. Sonet will automatically detect sound signals. The EXT cable has a red plug and provides signal only from the external audio source. The MIX cable has a yellow plug and will provide a mix between the external audio source and the microphones.