Design and implementation of a small scale PABX system using DSP technology

A flexible, low cost, and expandable digital private automatic branch exchange (PABX) system is developed. Digital switching and tone generation based on a digital signal processor are adopted. This reduces the overhead in assembling a small scale PABX system. The system can be expanded to handle more lines with the use of parallel processing techniques. A special software structure is developed to handle multiparty calls. The technique simplifies the programming of multiparty calls. Object-oriented design methodology is applied throughout the design of the call processing program. This results in a flexible program structure