The application of a communication infrastructure for hybrid test systems is currently a topic in the aerospace industry, as also in other industries. One main reason is flexibility. Future laboratory tests means (LTMs) need to be easier to exchange and reuse than they are today. They may originate from different suppliers and parts of them may need to fulfill special requirements and thus be based on dedicated technologies. The desired exchangeability needs to be achieved although suppliers employ different technologies with regard to specific needs. To achieve interoperability, a standardized transport mechanism between test systems is required. Designing such a mechanism poses a challenge as there are several different types of data that have to be exchanged. Simulation data is a prominent example. It has to be handled differently than control data, for example. No one technique or technology fits perfectly for all types of data. There are certain requirements that have to be fulfilled. For example, the mechanism for data exchange needs to have adequate performance to satisfy the demands of the industry. Another requirement is that it must rely on well-established standards to ensure stability and be future-proof. This paper describes the architecture of hybrid test systems, with special emphasis on the communication infrastructure. On the basis of this, it then analyzes the requirements for realizing a suitable communication infrastructure of hybrid test systems. Finally, it presents a proposal of how to devise a standardized interface to this communication infrastructure.