Earners of this badge will be able to describe examples of TETRA network architecture, including all IP networks, and why extra redundancy and resilience may be required. They will understand the function of core network interconnections, including the Intersystem Interface (ISI) and describe how the ISI may be deployed. They will also appreciate TETRA Network Areas, TETRA Identities, Talk Groups, Fleet Maps, and how various call transactions are set up and cleared down.