Panasonic KX-TG2257S - Manual (Page 78)

78
Adding Another Phone
This unit will not function during a power failure. To connect a standard
telephone on the same line, use the Panasonic T-adaptor KX-J66.
To order, call the accessories telephone number on page 2.
Standard Telephone
Single-Line
Telephone Jack
T-Adaptor (KX-J66)
Telephone
Line Cord