Simulation module, ONU (Optical Network Unit) equipment and communication fault diagnosis method

The invention provides a simulation module, ONU (Optical Network Unit) equipment and a communication fault diagnosis method and relates to a broadband access technology. The diagnosis method for a voice communication fault in a Passive Optical Network (PON) comprises the following steps that: the simulation module of the ONU equipment monitors a signaling message sent by a soft switch; the simulation module simulates operation of a user side according to the signaling message sent by the soft switch and generates a user side event message signaling to send to the soft switch; the simulation module monitors interaction of the signaling message with the soft switch and judges a fault point and reasons of the communication fault; and simulation module sends an error prompt message according to the fault point and the reasons of the communication fault. According to the invention, by simulation of the simulation module of the ONU equipment on the operation of the user side and the monitoring on the interaction flow of the signaling message, the fault point and the reasons of the communication fault can be judged so as to implement automation of diagnosis of the voice service fault.