A technique for training an equalizer of an ADSL Annex C transceiver is provided. At least two of the switches, which are preferably microelectromechanical or MEMS switches, reside on distinct physical substrate layers in the switching device, and at least one of the signals travels through a penetrable zone of one of the physical substrate layers. A rear spring and a front spring are attached to the brackets respectively for applying a closing bias force upon the inner arms respectively. Thus, the product corresponding to the order may be produced having the desired configuration.