The connection diagram is directly on the device. The ease of use directly on the radio is so-so and not comparable with the devices automaker or brand appliances. Therefore, to use better direct the remote control that has a good tactile feedback. The connection options are varied by USB, SD card, Bluetooth and AUX-IN. For me the device without any problems works. Compromises have to accept by the low price at ease and at the output. However, anyone who has solid boxes with amplifiers in the car, should give the radio a chance; because with devices around the 60 Euro you will hardly find a device with more features.