LOW VOLTAGE TELEPHONE TRANSMISSION CIRCUIT WITH DIALLER INTERFACE
The UTC TEA1062N/TEA1062AN is a bipolar integrated circuit
performing all speech and line interface function, required in the
fully electronic telephone sets. It performs electronic switching
between dialing speech. The circuit is able to operate down to D.C.
line voltage of 1.6V (with reduced performance) to facilitate the use
of more telephone sets in parallel.
* Low d.c. line voltage; operates down to 1.6V (excluding polarity guard).
* Voltage regulator with adjustment static resistance.
* Provides supply with limited current for external circuitry.
* Symmetrical high-impedance inputs (64kΩ) for dynamic, magnetic or piezoelectric microphones.
* Asymmetrical high-impedance inputs (32kΩ) for electrets microphones.
* DTMF signal input with confidence tone.
* Mute input for pulse or DTMF dialing.
* Receivering amplifier for several types of earphones.
* Large amplification setting range on microphone and earpiece amplifiers.
* Line loss compensation facility, line current depedant (microphone and earpiece amplifiers).
* Gain control adaptable to exchange supply.
* Possibility to adjust the d.c. line voltage
TYPICAL APPLICATION CIRCUIT