The ring network cabinet is composed of a ring-in and ring-out unit, a feeder unit, a PT unit, a DTU spacer unit (DAF-832 (M)), and a DTU common unit cabinet (DAF 830 (M)); the DTU common unit adopts an independent secondary cabinet, including the core device of the DTU common unit, a power management module, and a backup power supply; the DAF-832 (M) is embedded in the switch spacer secondary box, and its power supply is uniformly provided by the DTU common unit. The DAF-832 (M) spacer unit realizes the three remote, line loss acquisition, phase-to-phase and ground fault processing, and communication functions with the DAF-830 (M) common unit.