What is an Interoperability Layer? An interoperability layer is a system that enables easier interoperability between disparate information systems by connecting all of the infrastructure services and client applications together. In the OpenHIE context these systems are Health Information Systems (HISs) such as a client registry, provider registry, facility registry, shared health record and terminology service. An interoperability layer receives transactions from client systems, coordinates interaction between components of the HIE and provides common core functions to simplify the interoperability between systems. The interoperability layer developed by this community is the OpenHIM (Open Health Information Mediator),an open-source middleware system based on an ESB architecture and currently implemented in Rwanda as part of |