Panasonic KX-TG5480 - Manual (Page 12)

Installation
12
Connecting the Telephone Line Cord
Connect the telephone line cord(s) to the base unit.
If your unit is connected to a telephone line with DSL service, see page 14.
To connect to a 2-line telephone jack
4-Wire Telephone
Line Cord
with GREEN Plugs
2-Line
Telephone Jack
(RJ14C)
GREEN Plug