Method, device and system for monitoring working state of exchange boxes in real time

The invention discloses a method for monitoring the working state of exchange boxes in real time, which mainly comprises the following steps of: detecting the working state of each exchange box in real time, and updating the stored working state information of the exchange box when the working states of certain exchange boxes are detected to be changed; and when an enquiry command sent by a main control unit to enquire the working state change of each exchange box is received, returning a response containing the updated working state information of the exchange box and address information per se to the main control unit. The invention also discloses a sub-control unit and system for monitoring the working state of exchange boxes in real time. Through the scheme of the invention, a data server, the main control unit and the control unit in a file exchange system can synchronously acquire the working state of each exchange box and update the stored information in time, thereby realizing the real-time monitoring