Design And Implementation Of Network Interphone Based On GPRS

With the use of the Internet is increasing, IP telephone which is low cost intelephone calls has been widely used in the long distance telephone calls. Thecurrent IP telephone system usually is realized through the cable broadbandnetwork or WLAN network, although the cost is low, it constrain the range whenit is being used by users.In this paper, we put forward a network talkback system based on mobileGPRS grouping data business network, which needs send the sound data as apackage to the Internet through network. This system has many advantages, suchas wide coverage, low cost and easy to access. Its speech quality and continuationhave arrived at a practical level. This system mainly adopts wireless networkcommunication, embedded technology, speech processing technology, dataencryption technology and real-time location technology in terminal. Talkbackmodule uses low-cost microprocessor STM32F103whose core is ARMCortex-M3as the core processor. We design the whole hardware of this system,which adopts LM358and LM386to achieve the speech power enlargement,whose performance is good at speech input and output. We adopt GPRS moduleSIM300C to realize wireless network transmission. And we use NEO-5Q moduleto achieve real-time location of the hand-held terminal. We design the software torealize the control of all the sub module, and adopt G.729algorithm to compressthe speech data. Then we adopt AES encryption, which can keep the speech datasafe. To prove validity of each module, we put forward a testing project and giveout all the testing results of each module.GPRS network talkback system presented in this paper has the ability oftalking through the network between users. Its performance is good andreliability is high. It also satisfy the needs for encrypting the message in the talkand real-time location of the users.