A state-of-device remote monitor
system capable of applying a general-purpose line as a
transmission line for transmitting detection signals of a state of a device, comprises an on-the-spot area, and a
management area. The on-the-spot area includes an electric device, a
detector for detecting a device state of the electric device, and a first communication
signal converter for converting detection data obtained by the detection of the
detector into communication signals, and transmitting the communication signals. The
management area includes a second communication
signal converter for converting the communication signals received from the first communication
signal converter into the detection data before being converted by the first communication signal converter, a maintenance tool having a diagnostic / analytic program for analyzing the device state from the detection data converted by the second communication signal converter, and a maintenance
database stored with data necessary for the analysis by the diagnostic / analytic program and a diagnosed result, and a display unit for displaying the diagnosed result obtained by the analysis by the maintenance tool.