The shortwave radiocommunication between Antarctica and Beij- ing is the longest link at present time in China.

南极北京是我国目前最长的短波通信线路之一。

Maritime navigation and radiocommunication equipment and systems - digital interfaces - part 2: single talker and multiple listeners, high - speed transmission.

海上导航和无线电通信设备及系统。数字接口。第2部分：高速传送的单个通话器和多个受话器。