ETSI, in partnership with the Tetra and Critical Communications Association (TCCA), is about to embark on a series of interoperability tests to ensure that equipment from different vendors designed for mission-critical communication over LTE can work together. The trials, which will be carried out at ETSI's French headquarters in Sophia Antipolis, have been organised alongside pre-testing sessions with twenty vendors ahead of the association's Mission Critical Push to Talk (MCPTT) Plugtests event, taking place from 19 to 23 June.