 |
| |||
| однополюсное телеграфирование | |||
|
single- current system : 2 phrases in 2 subjects |
| Rail transport | 1 |
| Telecommunications | 1 |
|
| |||
| однополюсное телеграфирование | |||
|
single- current system : 2 phrases in 2 subjects |
| Rail transport | 1 |
| Telecommunications | 1 |