This document discusses TETRA terminals and extending network coverage using gateways and repeaters. It describes how gateways connect direct mode users to the trunked mode network, extending coverage. Repeaters are used to extend the range between direct mode users. The document provides examples of gateway and repeater applications. It also discusses product compliance and TETRA interoperability, noting that over 300 interoperability certificates have been issued to ensure equipment from different manufacturers can function together.