FlexRay, the prospective real time bus system, will expand the successfully used CAN bus for automotive applications. Its functionalities cover an enhanced transfer rate, deterministic real time capabilities and a time- and event-triggered transmission segment. Its great flexibility comes for the price of a huge amount of configuration parameters. The parameter set of a configuration covers more than 80 variables. A new kind of test systems is needed for testing such time division multiple access bus configurations for rapid system prototyping. In this paper we present a novel approach of a FPGA based test system. The introduced system can be used to check the composed network configuration to the real transmission on the physical bus. Furthermore, unknown network configurations can be analyzed and communication dependent parameters can be reported. This is done by sampling the data bit stream and dissecting the waveforms.