## 1 Introduction  
Companies involved in the design, manufacturing and marketing of complex mechatronic systems in aviation are subject to different constraints in their implementation. One of the constraints is the industry-standard requirement that products--such as airplanes--have a designated life time of 25 years or more after refurbishment [1] (p. 39). Products with this planned life span are referred to as sustainment dominated products [2]. The current regulations for certification stipulate that these products must remain maintainable and rectifiable [3] (p. 105).  
This constraint leads to consequences that are typical for modern mechatronic systems in aviation. Technical approaches that address the conditions are primarily implemented in information technology. Specifically, software development is considered the biggest driver in the development [2]. For them, correctness (of all developed components of a product) must be proven. The driving force in the correct development is not only the quality requirement of the manufacturer, but also the necessary government certification, as clearance for use in the legal space. For this purpose, test benches are used, which help the test engineer to execute requirement-based tests, to access the system under test (airplane systems) and to understand the results, as well as to store them for the entire life cycle.  
In the integration test phase, as part of the certification, the subsystem of the mechatronic system and the test bench form a temporary system. All test operations are only possible in this constellation. For this purpose, the test benches must support the technologies used in the mechatronic system over the entire life cycle. Continuous product changesand interim tests require the same lifetime from the test benches as from the actual product. It remains even when the product (airplane) is already past the certification phase (design phase) and is in the operation (usage phase) [3] (p. 105). Test benches are implemented from commercial off the shelf (COTS) components. They are designed for aerospace test benches only. The used components are produced in small series. They have an expected lifetime of three to seven years [2]. As a consequence, individual components in the test benches have to be replaced several times during their operational phase, in order to maintain the operational phase of the mechatronic system. These components are software, hardware and mixed forms of software and hardware. The affected components are no longer available on the market with the advanced service life. In order to mitigate the consequences of obsolescence, current approaches rely on hardware abstraction layers (HALs) [4]. This approach reduces the effort of the reimplementation in such cases. This article shows a proof of concept for a different approach, relying on the standardized I/O modules from the field of automation in production. An additional configuration approach will show the configurability of the I/O. This will enable the full interoperability and exchangeability of the I/O, not only at the system, but also at the syntax level. This approach enables the interconnection of test benches from different enterprises using different coding standards for variables inside the test benches, following the Industry 4.0 paradigm.