Audio can be heard from the vehicle's speakers by connecting a commerciallyavailable portable audio unit to the auxiliary jack.
A commercially-available, non-impedance (3.5 ) stereo mini plug cable is required. Contact an Authorized Mazda Dealer for details.
In addition, audio can be played from the vehicle audio device by connecting a USB device to the USB port.
NOTE
The SD card slot is for the navigation system. For vehicles with the navigation system, the SD card (Mazda genuine) with stored map data is inserted into the SD card slot and used.

WARNING
Do not adjust the portable audio unit or a similar product while driving the vehicle:
Adjusting the portable audio unit or a similar product while driving the vehicle is dangerous as it could distract your attention from the vehicle operation which could lead to a serious accident. Always adjust the portable audio unit or a similar product while the vehicle is stopped.
CAUTION
Depending on the portable audio device, noise may occur when the device is connected to the vehicle accessory socket. (If noise occurs, do not use the accessory socket.)
NOTE
Seek Switch
How to connect USB port/Auxiliary jackMazda 6 Owners Manual: Manual transaxle removal/installation
1. Remove the battery, battery tray and battery bracket.
2. Remove the air cleaner compornent. (See INTAKE-AIR SYSTEM
REMOVAL/INSTALLATION.)
3. Remove the wheels, tires and splash shields.
4. Remove the under cover.
5. Remove the steering gear and power steering pipe. (See STEERING GEAR AND
...
Mazda 6 Owners Manual: Picture Quality Adjustment
WARNING
Always adjust the picture quality of the rear view monitor while the vehicle
is stopped: Do not adjust the picture quality of the rear view monitor while
driving the vehicle. Adjusting the picture quality of the rear view monitor such
as brightness, contrast, color, and tint while dri ...