Patent ID: 7038597

Claim:
A railroad distributed power communication method for use with a plurality of wireless transceiver units at spaced locations along a train for determining which transceiver units from among the plurality of transceiver units are in receipt of a command message, the train having a lead transceiver unit for transmitting command messages and receiving status reply messages, where at least same of the plurality of transceiver units are remote transceiver units spaced from and outside of direct communication with the lead transceiver unit, and the train having at least one intermediate transceiver unit in direct communication with the lead transceiver unit and at least some of the remote transceiver units, the method comprising: transmitting a command message including a command instruction and a unique sequence number from the lead transceiver unit; receiving the command message at an intermediate transceiver unit and at least one of the remote transceiver units; storing data indicative of the command instruction and the unique sequence number of the command message received at the intermediate transceiver unit in a database associated with the intermediate transceiver unit; transmitting a respective status reply message from each of the at least one remote transceiver units for which the lead transceiver unit needs to verify receipt of the command message, each of the respective status reply messages including data indicative of the unique sequence number of the command message and a command function status of the respective at least one remote transceiver unit that transmitted the respective status reply message; receiving at least one of the respective status reply messages at the intermediate transceiver unit; storing data indicative of the command function status and the unique sequence number of the command message included in the received respective status reply messages received at the intermediate transceiver unit in the database associated with the intermediate transceiver unit; comparing the stored unique sequence number of the command message included in the respective status reply messages received at the intermediate transceiver unit to the stored unique sequence number included in the transmitted command message to determine if there is a match; if the compared unique sequence numbers match, comparing the command function status of the stored respective status reply messages to the command instruction of tile stored command message to determine which of the respective remote transceiver units is in receipt of the command message; preparing a second status reply message at the intermediate transceiver unit; setting a respective command received status bit in the second status reply message for each of the respective remote transceiver units that is in receipt of the command message; and transmitting the second status reply message from the intermediate transceiver unit to the lead transceiver unit.