err, your referring to the unitlock now?

thats something different from the bluetooth pin entirely...

when pairing two devices over bluetooth one just enters the same pin on both devices when requested (unless one of them have a hardcoded pin, keyboards and headsets have that most often).

some bluetooth devices, like computers, try to help the user by generating a random pin at its end each time that dialog comes up. if one accept that pin, one have to key the same pin in at the other end.