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近几年来,IP电话有了很大的发展,各类IP电话卡层出不穷,家庭电话也可开通IP直拨服务,那么较之传统电话,它到底有什么特别之处呢
In recent years, IP telephony has been greatly developed, all kinds of IP phone cards emerge in an endless stream, and home phones can also be opened with IP direct dial service. So what is special about the traditional phone?