The Study And Design Of LAN Communication Terminal Based On Embedded Linux System

Because of the increasing demands for communications, common voice communicationhas gradually failed to meet the everyday life of today, people putting more and more energyin seeking new avenues of communication. This terminal is designed to solve the problem ofthe lack of communication modes，which could only communicated by voice. We propose away to exchange voices and manuscript by synchronous transmission aiming at improving theregional language barrier in modern conference, work and education communicationconditions.The design take ARM11as core processor and Linux-based embedded platform. Thefunction of the device is to accomplish the handwritten board transmission(one to many ormany to one)while retaining the traditional voice communication demand. To give up theidea of using an analog circuit, the system uses an embedded microprocessor chip and a voicechip to deal with the real-time transmission of voice data. Also, the system is installed LCDscreen and touch screen, which enables simultaneous transmission of handwritten data andvoice data as possible. By using this device, the user can easily exchange voice or handwritingdata through the LAN with one or more users.This design mainly completes the real-time transmission of voice signal and handwrittenboard data. In the function of handwritten transmission, it uses the Qt mouse(touch) event torecord the cursor position so that the paint event can be touched off to write mouse trackingon class QImage. The implementation of voice real time transmission function mainly usesthe correlation function of the QtMultimedia module. A real-time signal should be recordedalternately into four buffering files. After that, a server-client should be built to complete thereal-time speech by TCP protocol.