PBX

PBX（专用交换机）简而言之就是集团电话，它被广泛地运用在企业办公机构中，极大地提高了企业的办事效率。但传统的PBX存在不少问题，首先是它对新兴的CTI（计算机与电话集成）和VoIP支持不够，而且传统的PBX都采用的是专用技术，缺乏开放性和标准性，并且价格昂贵。近年，随着Internet 的流行和IP的成功，基于IP协议的IP PBX应运而生，有望解决传统PBX的不足。 

PBX (Private Branch eXchange)

A phone switch located at the customer's premise. A PBX comes in many sizes, from 2 lines to thousands of phone lines. Common features include an ACD for call distribution and  that can process incoming phone calls prior to routing to call stations. Many PBX's support outbound dialing protocals such as autodialing, progressive dialing and . A PBX usually has many more features than a standard phone system.