This study’s motivation is to provide a reasonable and detailed procedure to achieve the coupling of general FE software with the control software in RTHS testing. Computational tasks are interconnected using a client-server communication approach. First, the client is chosen as a Matlab/Simulink program to implement the control algorithms for RTHS. Meanwhile, the servers are multiple OpenSees programs that simulate either numerical or experimental substructures. Examples of a virtual RTHS benchmark are provided to validate the integration method and illustrate the various uses of the client-server protocol, focusing on earthquake engineering applications. The results show good accuracy and real-time synchronization of client-server communication, allowing for the development of additional features of the Client-Server virtual Real-Time Hybrid Simulation (CSvRTHS) framework to model complex structural systems.