The objective of this proposal is to research, develop, and prototype an automated PC-based Virtual Testing Environment (VTE) that will allow the performance of tactical military radios to be tested and evaluated before deployment into an operational environment. The automated PC-based VTE will be based on OPNET COTS modeling and simulation software, and will allow the analysis and visualization of tactical radio datalink transmissions in a wide variety of scenarios to rapidly test and evaluate performance. The VTE will support system extensibility, interoperability, and scalability testing by providing a System-in-the-Loop (SITL) capability. The VTE will allow live testing of tactical IP-based radios by combining a SITL interface with an embedded simulation capability to allow interoperability testing with legacy system. The VTE will support scalability testing by providing the ability to model and simulate large-scale military networks using test radios, which is more affordable and lower risk than deploying a live multi-node test network. Currently, there is no commercially available automated virtual testing environment that adequately supports the DoD's comprehensive testing requirements for tactical radio systems. OPNET's proposal focuses on an automated PC-based VTE that provides a comprehensive test environment by combining OPNET COTS simulation software with a SITL interface to live tactical radios under test.