Restrictions on the parameters M and a given by given by the TD and TW models due to the QPO data simultaneously observed in the microquasar GRO J1655-40. The solid lines are given by the 3ν_L ~ 2ν_U twin HF QPOs resonance, while the dashed lines are obtained for the nodal frequency ν_nod that explain the LF QPOs at the same r_3:2 radius. The crossing of the twin HF QPO and the LF QPO limits implies the mass and spin of the black hole. The optical mass limit is shaded.