тональное телеграфирование
Frequency signaling, harmonic signaling, in-band signaling, harmonic telegraphy, tone telegraphy, voice-frequency telegraphy
Источник:
Полный русско-английский словарь
на Gufo.me
Frequency signaling, harmonic signaling, in-band signaling, harmonic telegraphy, tone telegraphy, voice-frequency telegraphy