[Novatek]

General Description

The NT91214/15 is a single-chip, silicon gate, CMOS integrated circuit with an on-chip oscillator for a 3.58MHz crystal or ceramic resonator. It provides a dialing pulse (DP) or dual tone multi-frequency (DTMF) dialing. A standard 4 x 4 matrix keyboard can be used to support either DP or DTMF modes.

Features

■ One touch redial operation

■ Tone/Pulse switchable

■ 32 digit capacity for redialing

■ Automatic mixed redialing (last number redial) of pulse to DTMF with multiple automatic access pauses

■ PABX auto-pause is 2.2 seconds

■ DTMF Timing:

Manual dialing: minimum duration for bursts and pauses

Redialing: calibrated timing

■ Hands-Free control function

■ Wide operating voltage range: 2V to 5.5V

■ Key-in beep tone output

■ Digits dialed manually after redialing are cascadable and stored as additional digits for the next redialing

■ Uses inexpensive ceramic resonator (3.58 MHz)

■ Two versions for different telephone systems

■ Built-in power up reset circuit

■ Four extra function keys: flash, pause, redial and DP or DTMF mixed dialing

■ 4 x 4 (or 2 x 8) keyboard can be used

■ Low standby current