carrier telephone repeater

high frequency telephone

multichannel carrier-frequency telephone terminal

negative impedance telephone repeater

single-channel carrier frequency telephone terminal

submerged telephone repeater

telephone frequency

Telephone Repeater

TR Telephone Repeater

Voice-frequency telephone channel

carrier frequency repeater

carrier frequency repeater equipment

high-frequency repeater distribution frame

Middle frequency-frequency convertor

VFREP Voice Frequency REPeater

voice-frequency repeater

video-telephone， viewphone， visual telephone

audio frequency and video frequency processing

Belgium OSB double frequency(work-intermediate frequency) Queching machine