GENERAL DESCRIPTION
The TEA1067 is a bipolar integrated circuit performing all speech and line interface functions required in fully electronic telephone sets. It performs electronic switching between dialling and speech. The circuit is able to operate down to a DC line voltage of 1.6 V (with reduced performance) to facilitate the use of more telephone sets in parallel.

Features
• Low DC line voltage; operates down to 1.6 V (excluding polarity guard)
• Voltage regulator with adjustable static resistance
• Provides supply with limited current for external circuitry
• Symmetrical high-impedance inputs (64 kΩ) for dynamic, magnetic or piezoelectric microphones
• Asymmetrical high-impedance input (32 kΩ) for electret microphone
• DTMF signal input with confidence tone
• Mute input for pulse or DTMF dialling
• Power down input for pulse dial or register recall
• Receiving amplifier for magnetic, dynamic or piezoelectric earpieces
• Large gain setting range on microphone and earpiece amplifiers
• Line current dependent line loss compensation facility for microphone and earpiece amplifiers
• Gain control adaptable to exchange supply
• DC line voltage adjustment capability