n.中央交换
A variation of a traditional Centrex telephony system is called IP Centrex. 传统的Centrex电话系统的另一种形式称为IP Centrex。
Centrex frequently uses analog telephone lines for the connections to a business or organization. Centrex经常使用模拟电话线路为公司或组织提供电话连接。
Centrex uses the telephone company's central office exchange to route internal calls back to an extension. Centrex使用电话公司的中央办公室交换机将内部电话又路由回到分机号码上。
Centrex telephony systems are sometimes used by larger organizations, but are most frequently found in government, public, and private organizations. 大型组织有时也使用Centrex电话系统,但多数是在政府、公共部门和私有组织中使用。
For example, with Centrex, the telephone exchange or telephone company's central office knows which extensions are internal. 例如,使用Centrex,电话交换机或电话公司的中央办公室将知道哪些分机是内部分机。
