Pairing with bluetooth model ask for security code again and again?

I have Bluetooth dongle attached to my laptop and some Bluetooth model trying to connect to my laptop and i paired that model but when after dissconnection , it again trying to connect it again ask for code i.e. 1234. I want to add model in this way that when in future it trying to connect it should connect automatically without ask for code or else. How could i achieve this?

help me thanks!