There are several tools that implement a whitelist with verification: TDMA is a popular multi-platform open source tool; ChoiceMail is a commercial tool for Windows; most others seem more preliminary.

这里有几种工具可以实现带验证的“白名单”：TDMA 是一个深受大家喜爱的多平台开放源码工具；ChoiceMail 是一个针对 Windows 的商业性工具；其它大多数似乎都比较初级。

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TDMA allocates each user a different time slot on a given frequency.

TDMA 在给定频率为每个用户分配不同的时隙。

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The algorithm for assigning TDMA time slot reduces overall delays of network.

采用TDMA时隙分配算法减少网络时延。

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Even when you look at cellular phones in the second generation you have four different standards: GSM, TDMA, CDMA, PDC.

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Economides said the agency had the opportunity to make the wrong choice back in the 1990s, when cellular carriers were bidding on spectrum for new digital systems and had to decide among the GSM, TDMA and CDMA standards.

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Traditionally, engineers who wanted multilingual phones had to laboriously design custom chips. ("Dual-mode" cell phones that can hop between, say, TDMA and GSM, have been around for years.) Once they are finally designed, such chips can be mass-produced cheaply and consume a reasonable amount of battery juice.

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