The paper also explains in detail the functions and effects of PABX?s switch modules and control modules about hardware structure and softwate implement. The scheme has been proved by several units and found application.

• 说明了实现此方案的两种类型模块：交换模块和管理模块的硬件结构各部分的功能和作用及软件实现的概况，此方案在200门至2000门模块化扩容程控交换机设计中得到理论和实验的论证，并在排队控制系统中有所应用