Description.
The PBL 388 13 contains all the necessary circuitry, amplifiers, detectors, comparator and control functions to implement a high performance, voice-switched, loudspeaking, ”hands-free ” telephone. The gain dynamics (attenuation between channels) is selectable (25dB or 50dB) via a separate pin. A background noise detector in the transmitting channel reduces the influence of continuous external noise signals to the switching .

KEY FEATUREs
• Minimum of external components needed for function.
• Selectable gain dynamics. (25 or 50 dB)
• Direct telephone line powered solution (patented).
• Low power consumption:≈1mA at 3.3V (typical) for speech switching, audio power amplifier quiscent current ≈1mA.
• Drives an 25 - 50 ohm loudspeaker without a transformer.
• Background noise compensation in the transmitting channel with hold function at receive.
• Input amplifiers of both channels have balanced inputs.
• Exellent noise performance.
• Encapsulated in 24 pin plastic ”skinny” DIP and 24 pin SO .