Completion of Calls on No Reply (CCNR) is an ISDN supplementary service offered to the calling user.

无应答时呼叫的完成(CCNR)是一种向主叫用户提供的ISDN补充业务。

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The ECT supplementary service enables an ISDN user who has two calls, into one call.

ECT补充业务能使具有两个呼叫的用户转移到一个呼叫中去。

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These procedures may be used for the invocation and operation of supplementary services in association with existing calls or outside any existing calls.

这些程序可以用于申请和运行与现存呼叫相关的或在任何现存呼叫以外的补充业务。

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