用于avaya系统的pbx的维护和巡检手册等等，主要为了服务语音通信的手册-Avaya pbx system for maintenance and inspection manuals, etc., primarily for voice communication service manuals

程控交换机模拟计费系统,计费原理，计费方式等功能的详尽说明，内附VF程序-A detailed descr iption of the analog PBX billing system, billing principle, billing and other functions, enclosing the VF program