The invention relates to an electrical contact t comprising a strip substrate comprising a conductive layer of a metal or an alloy provided on the surface of the substrate and an oxide layer provided on the conductive layer. Content included in the received items is observed to facilitate grouping the items. According to the invention, the edge propagation means are coupled with means of automatically detecting an emergence of the propagation edge from the imaged object at a current point. The non-parallel boundaries of the wall bump structures cause various pre-tilted directions for the liquid crystals filling the gap between two substrates. The shared extension has a shared call stack. This makes it feasible to configure a system by extending a conventional media convert type information communication system and to provide terminal users with media convert services with a much higher usability.