Methods and apparatuses for synchronizing a system clock of a computer via a local gateway are described herein. Said exchanger is characterized in that the casing is made of heat-resistant plastic material and means are provided for ensuring mechanical containment of the beam in the axial direction, and for damping the thrust loads resulting from the fluid internal pressure, preventing their being transmitted to the casing. These electrodes constitute interdigital electrode portions defined by mutually opposed comb electrodes which are arranged such that the direction in which the teeth thereof extend is substantially perpendicular to the length direction of the vibrating member.