The invention relates to an apparatus for examining documents, in particular documents of value, identification or security documents, having at least two detector units for detecting light emanating from a document to be examined. Methods are disclosed for producing such a construction, for forming an electrically conductive projection outwardly extending from a substrate, and for providing an electrical interconnection between adjacent different elevation areas on a substrate. The method includes connecting the pipe to the evaporation element and subsequently suspending the pipe and the connected evaporation element to the support structure, in a suspended position. After the mobile phone is connected, a bidirectional signal communication can be made between the mobile phone and the microphone and the speaker.