GENERAL DESCRIPTION

The TEA1112; TEA1112A are bipolar integrated circuits that perform all speech and line interface functions required in fully electronic telephone sets. They perform electronic switching between speech and dialling. The ICs operate at a line voltage down to 1.6 V DC (with reduced performance) to facilitate the use of telephone sets connected in parallel.
A current (proportional to the line current and internally limited to a typical value of 19.5 mA) is available to drive an LED which indicates the on- hook/off-hook status.

FEATURES

• Low DC line voltage; operates down to 1.6 V (excluding polarity guard)
• Voltage regulator with adjustable DC voltage
• Provides a supply for external circuits
• Symmetrical high impedance inputs (64 kΩ) for dynamic, magnetic or piezo- electric microphones
• Asymmetrical high impedance input (32 kΩ) for electret microphones
• DTMF input with confidence tone
• Mute input for pulse or DTMF dialling (MUTE for TEA1112 and MUTE for TEA1112A)
• Receiving amplifier for dynamic, magnetic or piezo-electric earpieces
• AGC line loss compensation for microphone and earpiece amplifiers
• LED on-hook/off-hook status indication
• Microphone mute function (MMUTE for TEA1112 and MMUTE for TEA1112A).

APPLICATION

• Line powered telephone sets, cordless telephones, fax machines and answering machines.