SYSTEM FOR TRANSMITTING WIRED DIGITAL INFORMATION

PROBLEM TO BE SOLVED: To provide a power source having high reliability for a network terminal and a subscriber terminal by allowing a management system not only to conform occurrence of trouble but also to locate a trouble location or the like. SOLUTION: At least one of subscribers Tln each having an end device is connected to a network terminal 2 via an electric line L3 and the network terminal 2 is connected to a line terminal 1 via a line L2 with a metallic conductor in its inside. The line terminal 1 is provided with a voltage source SV that supplies power to the terminal 1 and supplies power to the network terminal 2 and the end terminal of the subscriber. Two power supply units SVE1, SVE2 are placed in the network terminal 2, the one is used to supply power to active elements of the network terminal 2 and the other is used to supply power to the end terminal of the subscriber Tln. The two power supply units SVE1, SVE2 are connected to the voltage source SV of the line terminal 1 via separate conductors.