voice-frequency telegraph link

• 音频电报线路

voice-frequency telegraph link的用法和样例：

例句

1. A new telegraph line has been set up between the two cities.
   在那两个城市之间架设了一条新的电报线路。
2. On the technical side, telegraph lines are hard to maintain.
   从技术角度来说电报线路难以维修。