This paper introduces the basic principles of tone distribution and lode distribution networks in S1240 SPC exchanges, makes analyses and comparisons for the application ofrecorded announcement in tone distribution, and gives a examples to explain why.

• 作者对51240数字程控交换机中音信号分配原理和分配网络作了阐述，然后对音信号中录音通知音的应用进行了分析、较，最后举了设置一个音乐台的实例说明。