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4G的volte

 
因为4G LTE是个残缺的标准，4G LTE只定义了data,没定义voice，

所以各大公司自己搞了voice over lte标准，以借机树立贸易壁垒，搞准入制度

但是3G有voice,所以你的4G手机果不支持volte的话，以前都是用3G的voice

现在3g要关了，这样你的手机要么支持5G,要么支持4G LTE的VOLTE

否则就不能说话了


4G的volte其实有通用国际标准
但是美国各大电信公司都需要证书才能让你接入volte
否则不让你用，这就是白名单的来由
以前你从中国买的乐phone没有volte证书不让在美国用，
但是准对美国市场卖的一模一样的乐phone有volte证书
在美国用没问题
这样美帝把大量海外手机给彻底block了
这就建立了贸易壁垒
逼着你买美帝的iPhone

目前美国只有tmobile放弃了volte证书，
任何支持4G lte的手机都支持tmobile的volte
因为tmobile本质上是个外国公司

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