When i connect to my mobile device it asks me for a passcode.

Answer: The default pin code is "0000"

My friend give me a Bluetooth GPS, but i can't connect it by bluetooth Why?

Answer: Please check with your friend if it is work fine with his device before.

Can you help me step by step to set my RBT-1100 up and get it working.

Answer: You could follow user menu to setup it, or you may contact local retail for setup step by step.