At last , according to the feature of IN technology, this method gives some good ways to interwork with other data networks and it is convenient to develop the new services.

• 目前国内铁路区段、站场通信专用性较强,现有设备生产厂家众多,设备制式繁杂,且模拟制式居多,较难适应数字通信的发展,某些系统与程控交换机在功能上有所重复,影响通信效益。