I connected one phone with the F90 and it works fine, but fail with another phone. The phone is a samsung, AT&T, can not tell what model it is. In its bluetooth option, when it start activated, it searches for devices( the phone dos not have visibility option), then the phone screen says fail. Using the F90 unit, it also showed fail to detect the devices. So is it true that some bluetooth devices(the f90 and the phone) are not compatible and they will not work together?