近十几年来中国的电信事业飞速发展，电话网在急速地膨胀，目前已成为世界上第二大网，这已是举世公认的事实。迄今为止，电信业务中的主要成分仍然是电话业务（尽管数据业务也在急速发展之中）。因而以电话交换为特征的电话交换机，仍是通信网中的主要交换设备。 　　一、 网 In the past decade or so, the rapid development of China’s telecom industry and the rapid expansion of the telephone network have now become the second largest network in the world. This is a fact universally acknowledged in the world. To date, the main component of the telecommunications business remains the telephony business (although the data services are also rapidly evolving). Therefore, the telephone exchange characterized by telephone exchange is still the main switching equipment in the communication network. First, the net