A communication system comprising: a plurality of remote terminal units (RTUs) (301, 302, 303) configured to output a state signal; and a communication device configured to receive the state signal from each of the plurality of RTUs (301, 302, 303) and to generate signal quality information, which represents whether the state signal is normal or erroneous; characterized in that the communication system further comprises a control device configured to: receive the state signal from the plurality of RTUs (301, 302, 303) and the generated signal quality information through the communication device, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is normal, generate an analysis information on the at least one RTU that outputted the corresponding state signal on the basis of the state signal, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is erroneous, determine the at least one RTU that outputted the corresponding state signal as a load and generate an analysis information on the at least one RTU that outputted the corresponding state signal, and generate a system analysis information on the plurality of RTUs (301, 302, 303) based on the analysis information on each of the plurality of RTUs. a plurality of remote terminal units (RTUs) (301, 302, 303) configured to output a state signal; and a communication device configured to receive the state signal from each of the plurality of RTUs (301, 302, 303) and to generate signal quality information, which represents whether the state signal is normal or erroneous; characterized in that the communication system further comprises a control device configured to: receive the state signal from the plurality of RTUs (301, 302, 303) and the generated signal quality information through the communication device, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is normal, generate an analysis information on the at least one RTU that outputted the corresponding state signal on the basis of the state signal, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is erroneous, determine the at least one RTU that outputted the corresponding state signal as a load and generate an analysis information on the at least one RTU that outputted the corresponding state signal, and generate a system analysis information on the plurality of RTUs (301, 302, 303) based on the analysis information on each of the plurality of RTUs. receive the state signal from the plurality of RTUs (301, 302, 303) and the generated signal quality information through the communication device, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is normal, generate an analysis information on the at least one RTU that outputted the corresponding state signal on the basis of the state signal, in case that the signal quality information on the state signal received from at least one RTU among the plurality of RTUs (301, 302, 303) is erroneous, determine the at least one RTU that outputted the corresponding state signal as a load and generate an analysis information on the at least one RTU that outputted the corresponding state signal, and generate a system analysis information on the plurality of RTUs (301, 302, 303) based on the analysis information on each of the plurality of RTUs.