Patent ID: 8891547

Claim:
A link scanning method for cascaded remote control units RCUs, comprising: receiving, by cascaded RCUs, a link scanning message sent by a center control unit CCU, sending, by each of the RCUs except an end RCU, the link scanning message to an RCU in the next cascaded RCU through a remote end serial communication bus; generating, by each of the RCUs, a link scanning response message, sending, by each of the RCUs except an RCU directly communicating with the CCU, the link scanning response message to an RCU in the preceding cascaded RCU, and reporting the link scannin response message to the CCU cascaded RCU b cascaded RCU and directly sending, by the RCU directly communicating with the CCU, the link scanning message to the CCU; wherein the time when each of the RCUs except the end RCU sends the link scanning message to the RCU in the next cascaded RCU is the time when each of the RCUs receives the link scanning message, plus a preset time delay; or, the time when each of the RCUs, except the end RCU and the RCU directly communicating with the CCU, sends the link scanning response message received from the RCU in the next cascaded RCU to the RCU in the preceding cascaded RCU is the time when each of the RCUs receives the link scanning response message sent by the RCU in the next cascaded RCU, plus a preset time delay; and the time when the RCU directly communicating with the CCU sends the link scanning response message received from the RCU in the next cascaded RCU to the CCU is the time when the RCU receives the link scanning response message sent by the RCU in the next cascaded RCU, plus a preset time delay.