An electrical connector includes an electrically insulative holder member, a signal module formed of a circuit board with recessed holes, circuit lines, electrical contacts and via-holes and metal contact terminals and metal mounting terminals, and a metal shield. Agate is formed at a joint or an overlapped portion of two sewed ends of the protective net, and user-controllable and selectively openable fastening elements are provided on the protective net at the joint or within the overlapped portion corresponding to the two sewed ends to ensure safe closure of the gate of the trampoline safety fence. In one embodiment, a user interface device may include a plurality of permanent magnets and a plurality of multi-axis magnetic sensors to generate motion andor deformation signals to be provided to a processing element to generate the output signals.