A unique time-domain electromagnetic system and data processing technique which, using low frequency electromagnetic fields, can localize, in three-dimensions, the position of buried metallic objects is disclosed. The operation cable having a double layer structure is axially connected to a double layer cable that is constructed from a stay of a headrest and a push rod inserted into the tubular stay. The ferrule is disposed in the connector housing and projects from the front end of the connector housing. The method is dynamically adjustable allowing for varying numbers of data inputs.