| http://www.w3.org/ns/prov#value | - Carrier communication apparatus adapted to be bridged onto a first wire-pair, the apparatus including microphone and loudspeaker transducers for converting audible sounds into voiceband electrical signals, a first modulator for converting the voiceband electrical signals from the microphone transducer into a first frequency band above 4 kHz, and a first demodulator for converting modulated signals
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