Device control system

A device control system comprising:

• a plurality of target devices to be controlled;
• and
• a plurality of controllers that remotely control the plurality of target devices,
• wherein each of the plurality of controllers comprises:
• an input means that receives an operation of a user as a control instruction;
• a display means that displays information associated with the control instruction;
• a communication means communicable with each of the plurality of target devices and each of the other plurality of controllers;
• a first information obtaining means that communicates with each of the target devices and each of the other plurality of controllers to obtain first information via the communication means, the first information representing that each of the target devices is operative and each of the other plurality of controllers is operative;
• a second information obtaining means that communicates with each of the target devices to obtain second information via the communication means, the second information representing that each of the target devices is lastly controlled by which of the plurality of controllers;
• a determining means that refers to, when receiving a first control instruction to control a first target device in the plurality of target devices via the input means, the first information and the second information to determine whether an other controller whose control instruction conflicting with the first control instruction is present in the other controllers;
• a third information sending means that creates, when the determining means determines that an other controller is present in the other controllers as a conflicted controller, third information indicative of operational information of the first control instruction, and sends the created third information to the conflicted controller via the communication means;
• a device control means that controls the first target device in accordance with the first control instruction when receiving, from the conflicted controller, reply information via the communication means, the reply information representing that the first control instruction is approved;
• an output control means that displays, when receiving the third information from an other controller via the communication means, operational information represented by the third information on the display means;
• a first input control means that receives, as the reply information, information representing whether to approve or disapprove the first control instruction and inputted via the input means;
• and
• a reply information sending means that sends, via the communication means, the reply information to the other controller that has sent the third information.