You will need to input on both Bluetooth devices only once on the first time you connect them to each other.
This pass code needs to be the same on both devices:
For devices which offer the possiility to input a pass code in their user interfaces, the pass code can be any digits chosen by the user as long as the same digits are entered in the player and the device.
For devices which do not offer the possibility to input a pass code devices like Bluetooth stereo headphones, then use a default pass code (normally 0000, but also in some device 1234 or 8888 is used).
HINTS: You are advised to find this pass code from the user manual of the Bluetooth stereo headphone, home, or car audio system.