A receptacle module capable of suppressing deterioration of characteristics of optical signals transmitted in optical fiber cables even when an external force is applied in a direction orthogonal to a longitudinal direction in a state where an optical fiber connector is attached in a receptacle. A remap table is used to map all logical addresses from a host system to the actual physical addresses where data are stored. A lower core is inserted into the first recess of the body, and a coil is wound around an insulating material installed at the lower core for detecting an induction current. At the source node, a common path identifier that identifies the data path is encoded into a request that is sent to the end node for identifying a particular data path that terminates at that end node, and for returning a data network address associated with that data path. The inventive system can also be used to measure distances e.