In this paper, we introduce a combinatorial test generation research tool called Advanced Combinatorial Testing System (or ACTS). ACTS supports t-way combinatorial test generation with several advanced features such as mixed-strength test generation and constraint handling. To facilitate its use and integration with other tools, ACTS provides three types of external interface, including a graphic user interface, a command line interface, and an application programming interface. ACTS is a freely distributed research tool and has been downloaded by more than 1200 companies and organizations.