Open communication describes internationally agreed standards with which open systems work and defines the rules for implementing these standards.
Open communication systems are defined as a combination of network hardware and network and system software that allows the unrestricted exchange of information between these devices based on common protocol agreements and interfaces, regardless of the other design and equipment of these devices. Systems implementing OSI protocols are an example of this. The basis for open communication was laid with the OSI reference model.
The OSI standards are freely available and not protected by licenses.