voice-frequency

Тональная телеграфия voice-frequency patching bay — стойка тональной коммутации voice-frequency ringing generato — вызывной генератор звуковой частот — voice-frequency channel — voice-frequency dialing — voice-frequency dialling — voice-frequency generator — voice-frequency receiver — voice-frequency ringer — voice-frequency ringing — voice-frequency signal — voice-frequency telegraph — voice-frequency telephony