| 摘要 |
<p>A telephone adapter for hands-free telephony, adapted for use with a telephone handset having structure including an earpiece, and a microphone handset. The adapter comprises a transmit signal path comprising, in series, a microphone, an amplifier, a switch and a transducer; and a receive signal path having amplifier for sound energy from the earpiece. The receive path comprises, in series, a coupler, an amplifier, a switch and a speaker. A bias maintains the transmit path in an active state when no signals are present; and a circuit interrupts the circuit paths in a complementary manner.</p> |
