Research And Development Of Voice Communication In Digital Trunked Dispatching System Server

TETRA digital trunking system is a special mobile communication system for commanding, dispatching and emergency communication. Dispatching system is an important component of the digital trunked communication system. It is made of dispatching client and dispatching server, the dispatching client provides an operation platform for dispatchers to control and command which can greatly improve work efficiency. Dispatching server provides API interfaces for dispatching client to access into the digital trunked network, and also takes charges of complex signals processing in the trunked system.Dispatching server solution over IP in the digital trunked system is proposed based on the development of the domestic and foreign digital truned dispatching system in this paper. The dispatching server is a standard TCP/IP local server. It provides the API interface of user login, call services, short data services, user management, and talk group management interface for the dispatching client. The dispatching client uses socket method to access the dispatching server and implements the control and command functions. The communitation between the dispatching server and the digital trunked exchange system is according with the air interface protocol of digital trunked system by using IP protocol. The transform and the process of the signals is implemented inside the dispatching server. The voices are transferred by using RTP protocol.In addition, the sequence charts of individual call, group call, calling group monitoring, call waiting and so on are designed. The dispatching server software is developed by using the Qt Creator as the developing tools and Linux operation as software invironment, the software of dispatching server is also tested. The result of the test indicates that the dispatcher software is satisfied to the targer of the design.