The invention provides a support structure for a mobile communications device comprising a dampening mechanism to dampen the insertion of the mobile communications device into the support structure wherein the dampening mechanism comprises a geared arrangement to control the speed of insertion of the mobile communications device into the support structure. The vertical localized charge-compensated trenches include at least a pair of opposite conductivity type semiconductor layers. The controller is configured to produce, as a voltage of the signal for the communication, from the third voltage, one of the first and second voltages corresponding to a determination result of the determiner.