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1·When the subscriber begins to answer, the telephone link to the subscriber has been established and the charging period comes into effect.

当用户回答时，便意味着到用户的电话线路已经建立，并且开始计费。

2·Making use of microcomputer techniques, the interface collects information from common control exchange HJ-921 and repeats called subscriber number to rural telephone exchange.

该接口利用微型计算机技术从HJ—921型交换机的公共控制设备采集，并向农村支局自动交换机转发被叫用户号码。