With the convergence of the communication technology and the computer technology, traditional telephone switching has evolved into the present B-ISDN, and is go on to advance towards the trend of high-speed and intelligence.

• 随着通信技术与计算机技术的不断融合和发展，传统的电话交换网络已发展成为今天的宽带综合业务数字网B-ISDN，而且还将继续向着高速化和智能化的方向发展。