An efficient solution to transform an output from a single ended source to a pair of differential signals that are provided to a differential receiver. The invention also provides an edge apparatus, a L2 VPN and a method for providing pseudo wire service in PSN. When the received user ID matches the user ID added to the job information, the image forming apparatus A transmits a request message including the user ID and for establishing linkage with other image forming apparatuses B and C. Each metal pipe is inserted through the through hole and thereby guided to be moved in its axial direction inside the supporting portion. The interconnections are arranged to close when the vehicle speed increases so as to provide roll control.