The Research In Dmr (Digital Mobile Radio) Repeater Mode And An Implement Of PSTN Interface

With more and more demand of trunking communications and the development of communication technology, trunking communications has been from analog to digital mechanism. Many International Standards Organizations have launched its own characteristics of the communication protocol. DMR (Digital Mobile Radio), developed by European Telecommunications Standards Institute (ETSI) in 2005, is causing more and more attention. Based on the DMR Tier2, this paper design a repeater interface between DMR transit stations and PSTN networks to achieve expansion of the function of communication distance. The paper first introduces the repeater mode and the process of the DMR, and then, proposes an plan about how to select chips and design the circuit and the program to meet the requirement of the voice communications between DMR mobile station and the PSTN customer. At last, the function of each module of the design has been tested. At the same time, in order to provide a good operating system platform for programming, this paper has also studied the process of transplanting the embedded Linux kernel on AT91RM9200.