Patent ID: 7957313

Claim:
A diagnosis apparatus connected to a communication bus of a TDM communication system in which a plurality of time slots are assigned respectively to a plurality of nodes, each of the plurality of nodes periodically transmitting a frame in a corresponding one of the plurality of time slots, the frame containing an identification code of the corresponding time slot, the diagnosis apparatus for diagnosing a diagnosis object associated with the TDM communication system, the diagnosis apparatus comprising: means for decoding a communication signal associated with the frame, the communication signal inputted from the communication bus, the decoding for specifying the identification code and a reception time of the frame; means for storing the reception time and the identification code specified by the decoding means; means for estimating a transmission period of the frame, the diagnosis object including the time slot, the estimating based upon the reception time and the identification code stored in the storing means; means for determining whether the frame is transmitted in the transmission period estimated by the estimating means in the time slot after estimating the transmission period by the estimating means, the determining based upon the reception time and the identification code of the frame specified by the decoding means; means for providing a notification of a failure of the TDM communication system when determining means determines that the frame is not transmitted in the estimated transmission period; means for detecting an upward edge, in which the communication signal is switched upward, and a downward edge, in which the communication signal is switched downward, and measuring a communication velocity in communication between the plurality of nodes through the communication bus, the measuring based upon the communication signal inputted from the communication bus and a length between the upward edge and the downward edge, wherein the decoding means is arranged to decode the communication signal inputted from the communication bus, the decoding corresponding to the communication velocity measured by the measuring means to specify the identification code written in the frame and the reception time of the frame contained in the communication signal.