 |
| |||
| main exchange; parent exchange | |||
| central switching office; central exchange; central office; district exchange; primary exchange | |||
| central principal: 13 phrases in 5 subjects |
| General | 4 |
| Mechanic engineering | 2 |
| Politics | 1 |
| Technology | 4 |
| Telecommunications | 2 |
|
| |||
| main exchange; parent exchange | |||
| central switching office; central exchange; central office; district exchange; primary exchange | |||
| central principal: 13 phrases in 5 subjects |
| General | 4 |
| Mechanic engineering | 2 |
| Politics | 1 |
| Technology | 4 |
| Telecommunications | 2 |