In this paper, after analysing the status on public and private PSDN, the significance of standard-based value added service systems is indicated.

本文介绍了公用和专用分组交换数据网的现状后，说明了开展标准的增值业务系统的重要性。

youdao

In this paper, after analysing the status on public and private PSDN, the significance of standard-based value added service systems is indicated.

本文介绍了公用和专用分组交换数据网的现状后，说明了开展标准的增值业务系统的重要性。

youdao