摘要
笔者根据对虚拟交换机与传统用户小交换机同时使用两年多的经验和体会，分析比较二者的利弊，供其他电信用户在制定有关方案时参考。
The author, based on over two years' experience of using both central exchange and private branch exchange, makes a contrastive analysis of the advantages and the disadvantages of the two for other telecom end - users to refer to.
