The Study On The Heterogeneous Communications Platform Technology Based On H.323 Protocol

The communications network of emergency command system often structure by several independent but complementary communication system,and these different systems worked together and formed a emergency command system platform which includes the IP,GSM/CDMA,wired/wireless communications network。The communications network equipment is often used independently,which unable to meet the needs of a variety of command mode。so we need to construct a heterogeneous communication platform which integrated with a variety of communication,in order to meet the needs of emergency command system。This paper is also improves the key technologies about the heterogeneous communication platform.Based on the H.323 call control module,designed the telephone and PSTN terminal call control module's terminal state machines and state transition tables,and offered a particular design about the H.225.0 call signaling module . Goertzel algorithm is improved to enable more accurate detection of the DTMF numbers and detect the phone working state by increasing the detection parameters.This paper improves the method of mixing audio:first,the mixing sources are improved by enhanced the low audio data; second,follow the step method for dynamic weighting of the mixing audio:and finally the improved algorithm was evaluated.In the silence detection algorithm,this paper presents a self-adaptive silence detection algorithm,the algorithm can adjust its detection threshold to current yawp environment, the performance of the silence detection get some improvements。This paper designs a heterogeneous communication platform which could assemble a lot of different types of terminal,and adopts VOIP technologies (make use of H.323 protocol)。In this program,three different kinds of Gateway hardware are designed and point to point communication,multi-point conference are also implemented in four types of communication terminals。the communication terminal state monitoring and conference management capabilities are provided to users。Finally,heterogeneous communication platform was successfully achieved based on the H.323 protocol。The author constructed an experimentation environment and made a comprehensive test on the system, give the result report。...