W is a digiul trunkin mobile cominunhaon system based on mma forhnology it offers group call diw w m wion ( dmo ) , duplex phone tall , padri data sehece , short data service and so on . tetw supports air interface and end - bend encrypon . tem is not only a fit private system for dispateh cominedcation of the polieq fire servce " w ha wtport , city tiwhc eto , but also for ule project reqthements of the public tw communication system Tetra是一种基于时分复用( tdma )技术的数字集群移动通信系统，它可以提供组呼调度、脱网直通( dmo ) 、企双工电话、分组数据服务、数据短信息服务等业务，支持空中接口加密和端到端加密功能，既适合公安、消防、机场、铁路、城市交通管理等专业部门调度指挥专用，也可满足社会共用集群网的设计要求。
