现代通信网技术与发展（下）张维华上海市邮电管理局副局长总工程师二、上海通信网发展的对策上海的通信网正经历着其历史上发展最快、变化最快的时期。制定合理的技术对策，对广海通信网的健康发展是非常重要的。１．公共电话网（ＰＳＴＮ）上海公共电话网是上海邮电目前... Technology and Development of Modern Communication Network (Part Two) Zhang Weihua Chief Engineer, Deputy Director, Shanghai Post and Telecommunications Administration Second, Countermeasures for the Development of Shanghai Communication Network Shanghai’s communication network is experiencing the fastest-growing and fastest-changing period in its history. Making reasonable technical countermeasures is very important to the healthy development of Guanghai Communication Network. 1. Public telephone network (PSTN) Shanghai public telephone network is Shanghai Posts and Telecommunications currently ...