According to the upgrade and transformation requirements put forward by the power dispatching automation system, it is required to connect the site that has not yet been connected to the local tuning and tuning system to the localization and adjustment system through the dispatching data network, realizing the integration of the multi-scheduling system. However, some remote engines that are being used in substations do not have enough interfaces to access multiple dispatch systems at the same time. To this end, a serial interface shunt device is designed by analyzing the working mode of the telecontrol communication protocol of the dispatching master station and the substation. By connecting the device to the substation's remote engine, real-time communication between the remote engine and multiple dispatching automation master stations can be realized. The application of the branching device enables the substation to realize the real-time monitoring and dispatching of the substation by multiple dispatching main stations without replacing the remote motives, meeting the integrated access requirements of the electric power dispatching system through testing and pilot operation. This work is supported by National Natural Science Foundation of China (No.61561018).