Panasonic KX-TD612E User Manual page 18

1.4 Adding Another Telephone in Parallel (EXtra Device Port [XDP] )
Method 2
4-conductor wiring cord
Connect pins "H" and "L" only.
("T" and "R" are not required.)
Digital Proprietary Telephone
Method 3
Double Modular Socket
4-conductor wiring cord
For a digital proprietary telephone:
Connect pins "H" and "L" only.
("T" and "R" are not required.)
18
Modular
Socket
Single Line Telephone
Digital Proprietary Telephone
Modular
Socket
2-conductor wiring cord
Connect pins "T" and "R".
Distribution
Frame
2-conductor wiring cord
Connect pins "T" and "R".
Single Line Telephone
Overview