This part is a kind of semiconductor called K2411.
Function of this product has Telephone Tone Ringer.
Manufacturers : Forward Holdings
Image and pinout :
Some of the text within the PDF file :
FORWARD INTERNATIONAL ELECTRONICS LTD. SEMICONDUCTOR TECHNICAL DATA K2411 TELEPHONE TONE RINGER The 2411 is a bipolar integrated circuit designed for telephone tone ringer. Features * Designed for telephone bell replacement * Adjustable 2-tone frequency * Hysteresis circuit prevents false triggering and rotary dial “Chirps” * Adjustable for reduced supply initiation current Package: DIP-8 Pin No 1 2 3 4 5 6 7 8 Name VCC RSL LFI LFO GND HFO HFI OUT Function Power supply (+) Resistor select Low freq osc input Low freq osc output Ground (-) High freq osc output High freq osc input Signal output 1 2 3 4 8 7 6 5 ABSOLUTE MAXIMUM RATING Parameter DC Supply Voltage Power Dissipation Operating Temperature Storage Temperature Symbol Vcc Pd Topr Tstg Rating 36 450 -25~+75 -55~+125 Unit V m [ ... ]