This part is a kind of semiconductor called KX-TS500MX.

Function of this product has Telephone Operating Instructions Manual.

Manufacturers : Panasonic

Image and pinout :

Some of the text within the PDF file :

1 Integrated Telephone System Getting Started 1-B Settings 1 2 Connect the telephone line cord (1). Connect the handset cord (2), then confirm the dial tone. VOLUME (^), (_) Buttons (2-A) 2 3 Set the DIALING MODE selector to TONE. ≥If you cannot dial, set to PULSE. DIALING MODE Operation 3 Special Features 1-A Location of controls DIALING MODE Selector (1-B) RINGER Selector (1-B) 2-A Making Calls 1 2 3 Telephone Line Cord 3-A For Call Waiting Service Users Press (FLASH) if you hear a call-waiting tone while talking. ≥The first call is put on hold and you can answer the second call. ≥To return to the first caller, press (FLASH) again. Operating Instructions Model No. Lift the handset. Dial a phone number. ≥If you misdial, hang up and start again from step 1. KX-TS500MX [ ... ]

KX-TS500MX PDF Datasheet Download