In this paper we will present an educational software designed for signal and speech processing applications. This interface which was developed under Matlab, can be used for signal denoising, speech coding and recognition. The implemented algorithms take into account the G723-G729 UIT specifications. The main menu was divided into six under-menus devoted for signal waveform representation, signal processing, signal segmentation and indexing, speech analysis and speech coding. The software has the advantage to operate in real time (acquisition from sound card and matlab processing) thanks to the Matlab data acquisition system. Nevertheless, the user can uses a signal or a speech database for signal processing. The obtained results are compared with other famous softwares such as Praat, Speech Analyser and Phonedit especially with various waveform signals.