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| neutral direct-current telegraph system (ток протекает только во время посылки); single-current system | |||
| on-off telegraphy | |||
| single-pole telegraphy | |||
| on-off telegraph; single-current signaling | |||
| single-current transmission | |||
| continuous wave telegraphy; single-current signalling | |||
| однополюсное телеграфирование: 3 短语, 3 学科 |
| 媒体 | 1 |
| 技术 | 1 |
| 电信 | 1 |