Connecting pins are provided at connecting portions on the airbag device side in such a manner as to project therefrom, whereas connecting levers adapted to rotate in directions normal to an axial direction of the connecting pins are disposed on the main body side. A terminal cellular bridge enables the retrieval of data from, and the sending of data to the aircraft by an internet service provider. A next step includes training the finite-impulse-response filter with a set of symbols of specific quadrature phase, known a priori, in the burst of data of the received waveform.