This part is a kind of semiconductor called KX-TA616.

Function of this product has (KX-TA616 / KX-TA308) Advanced Hybrid Systems.

Manufacturers : Panasonic

Image and pinout :

Some of the text within the PDF file :

( DataSheet : ) KX-TA308 KX-TA616 The Best Solution For Your Communication Needs The telephone is your main source of communication - your link to business partners, customers, friends, and even your family members both inside and outside the office. The KX-TA308 and KX-TA616 Advanced Hybrid Systems are phone systems which can support your business and personal needs. The KX-TA308 supports 3 outside (CO) lines and 8 extensions. The KX-TA616 supports 6 outside (CO) lines and 16 extensions. With optional cards, you can easily expand your system capacity up to 6 outside (CO) lines and 24 extensions* as your needs grow. Both systems provide the features that satisfy the demands of the most sophisticated and cost conscious users. Y [ ... ]

KX-TA616 PDF Datasheet Download