The En Route Automation Modernization (ERAM) program is a real-time Air Traffic Control (ATC) program being developed by Lockheed Martin Corporation. The ERAM program has high availability requirements, mission critical applications, and stringent response time requirements. The estimated size of the ERAM program is 1,300 KSLOC and includes primarily Ada, C, and C++ code. Legacy code being reused in ERAM is both Ada and C. This resulted in the need for several cross-language interfaces. Standard methods for passing binary data structures between the languages have been developed and will be discussed in this paper.