GENERAL DESCRIPTION

The SA2531 is a CMOS integrated circuit that contains all the functions needed to form a high performance electronic telephone.

The device incorporates LD/MF repertory dialling, melody generation, ring frequency discrimination and a high quality speech circuit.

A RAM is on chip for a 31 digit last number redial and 14 memories each containing up to 21 digits. The sliding cursor procedure makes Last Number Redial easy behind a PABX.

The SA2531 (exept the SA2531D) incorporates a volume control for the earpiece. The receive volume can be controlled by the VOL key (+4dB) or by the +/- keys (+6dB/-4dB in 5 steps).

The versatility of the circuit is provided by on chip programmability and a few external components. This allows easy adaption to different PTT requirements without changing the PCB of the telephone.

■ Speech circuit, LD/MF Repertory Dialler

and Tone Ringer on one 28 pin CMOS

chip

■ Net 4 compatible

■ Soft clip to avoid harsh distortion

■ Line Loss Compensation selectable by

pin option

■ Power down mode

■ Versatile applications for different PTT

demands

■ 31 digit last number redial

■ Sliding Cursor protocol with comparison

■ 2 Flash keys, 100 ms and 280 ms (option

600 ms)

■ Ring frequency discrimination

FEATURES

■ Operating range from 13 to 100 mA

   (down to 5 mA with reduced performance)

■ Volume control of receive signalExcept "D")

■ Low noise (max. -72dBmp)

■ Real or Complex impedance on chip programmable

■ LD/MF switchable dialling

■ 14 memories, 4 direct/10 indirect or 10 direct

■ Pause key for 2, 3 or 6 sec Auto Pause or Wait function

■ On chip MF filter (CEPT CS 203 compatible)

■ 3-tone melody generator