| |||
| 回送; 返回 | |||
| 环回; 数字环回; 数字环回测试 | |||
|
loop back : 27 phrases in 13 subjects |
| Aviation | 1 |
| Computer networks | 2 |
| Electric machinery | 1 |
| Electronics | 1 |
| Figure skating | 6 |
| Information technology | 3 |
| Metallurgy | 1 |
| Oil / petroleum | 1 |
| Rail transport | 1 |
| Skydiving | 2 |
| Space | 1 |
| Technology | 4 |
| Telecommunications | 3 |