随着通信技术的发展，我国的主干线传输网已基本上实现了有线光纤化、无线数字微波和卫星化。绝大多数乡镇交换节点也实现了数字程控化。作为用户来说，也不仅仅满足于普通的电话服务，而希望接入宽带的信息高速公路，享受多种通信业务的服务。但由于用户接入线的接入速率受到 With the development of communication technology, China’s trunk transmission network has basically realized wired optical fiber, wireless digital microwave and satellite. The vast majority of township exchange nodes have also achieved digital programming. As a user, it is not only satisfied with the ordinary telephone service but also wants to access the broadband information superhighway and enjoy the services of various communication services. However, due to user access line access rate