一、引言Information Gate keepers公司和通信、信息系统公司对成本对比的研究,是基于在美国电信业务供应局(公共公司)从尽可能降低长期运行成本的观点出发来评价有竞争力的产品所采用的方式的基础上进行的,这里所说的长期运营成本也叫做年度成 I. INTRODUCTION Information Gate Keepers and Communications and Information Systems Research on cost comparisons is based on the evaluation of competitive products at a point where the US Telecommunication Services Supply Bureau (public company) seeks to minimize long-term operating costs as much as possible On the basis of the way, here said the long-term operating costs are also called annual