Traditionally, such a circuit was provisioned through the use of two copper pairs, one for transmission ( forward path , or upstream path ) and one for reception ( reverse path , or downstream path );

传统上，这种电路通过使用两个铜电缆对提供，一个用于发送（前向路径或上游路径）、一个用于接收（反向路径或下游路径）。

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Traditionally, such a circuit was provisioned through the use of two copper pairs, one for transmission ( forward path , or upstream path ) and one for reception ( reverse path , or downstream path );

传统上，这种电路通过使用两个铜电缆对提供，一个用于发送（前向路径或上游路径）、一个用于接收（反向路径或下游路径）。

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