Heating and current drive by electron cyclotron waves in high magnetic field tokamaks is commonly done by coupling power from the low-field side to the O-mode. However, for tokamaks with ωpe/ωce>1, such as the spherical tokamak NSTX, the O-mode is cutoff throughout most of the plasma. An alternative method for accessing the cyclotron layer is via the fast X-mode and its mode conversion to an electron-Bernstein wave (EBW)[1]. We show that for a given plasma density and magnetic field profile, an appropriate choice of the frequency allows one to form a triplet (cutoff-resonance-cutoff) X to EBW mode-conversion scenario. This is similar to the low-frequency, ion-ion hybrid resonance scenario for which 100% mode conversion was shown to be possible[2]. The mode-conversion efficiency for DIII-D and NSTX is calculated.