Telephonic communications – Supervisory or control line signaling
Patent
1987-04-06
1988-10-04
Dwyer, James L.
Telephonic communications
Supervisory or control line signaling
379395, 379362, 379418, H04M 126
Patent
active
047760087
ABSTRACT:
A key-in sound-generating circuit comprises a keyboard including dial number keys and function keys, a DTMF signal generator coupled, at the output terminal, with a telephone network, a sound generator for converting, into a sound, the output signal from the DTMF signal generator, and a data processor circuit for executing the key data processing according to the keying operation performed using the keyboard, and supplying a control signal to the DTMF signal generator, the data processor being responsive to the operation of the dial number key, to supply a DTMF signal to the keyboard and the sound generator, and responsive to the operation of the function key, to supply a single-frequency signal to the keyboard and the sound generator.
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Dwyer James L.
Kabushiki Kaisha Toshiba
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