This part is a kind of semiconductor called LS1240.

Function of this product has Electronic Two-Tone Ringer.

Manufacturers : Wing Shing Computer Components

Image and pinout :

Some of the text within the PDF file :

LS1240A Electronic Two-Tone Ringer . . . . . LOW CURRENT CONSUMPTION, IN ORDER TO ALLOW THE PARALLEL OPERATION OF 4 DEVICES INTEGRATED RECTIFIER BRIDGE WITH ZENER DIODES TO PROTECT AGAINST OVERVOLTAGES LITTLE EXTERNAL CIRCUITRY TONE AND SWITCHING FREQUENCIES ADJUSTABLE BY EXTERNAL COMPONENTS INTEGRATED VOLTAGE AND CURRENT HYSTERESIS Minidip DESCRIPTION LS1240A is a monolithic integrated circuit designed to replace the mechanical bell in telephone sets in connection with an electro-acoustical converter. It can drive directly a piezoceramic converter (buzzer)or a dynamic loudspeaker. The output current capability of LS1240A is higher than standard ringer. For driving a dynamic loudspeaker LS1240A can simply use a decoupling capacitor, thus eliminating the usual transformer. No current l [ ... ]

LS1240 PDF Datasheet Download