Systems are often operated by not integration but blocking, i.e., non-standardization. The system blocking is mainly caused by non-standardization or incompatibility. The integrated system is effective, but researches for quantification of effectiveness from integrating system are few. System blocking causes additional cost which is almost intangible and potential. In this paper we proposed a model to quantify the effectiveness of system integration. To verify the validity of proposed model, we applied the model for Korean information and communication industry and forecasted the cost of integration for South and North Korean telecommunication industry in the way of three scenarios.