Panasonic KX-TD500 System Reference Manual page 136

4.02 Parallel Connection - DPITS
Any Single Line Telephone can be connected parallely with Digital Proprietary Telephone
as follows:
1) Connection with Modular T-Adaptor
To DHLC card
2) Connection with XDP port
To DHLC card
Proprietary Telephone
KX-T7220
KX-T7230
KX-T7235
KX-T7250
To DHLC card
4-conductor wiring cord
Modular
T-Adaptor
2-conductor wiring cord
4-conductor
wiring cord
Proprietary Telephone
KX-T7220
KX-T7230
KX-T7235
KX-T7250
To EMSS To TEL
2-conductor wiring cord
2-C-58
Panasonic KX-J66
or
USOC RJA2X
Single Line Telephone
4-conductor wiring cord
2-conductor wiring cord
To SLT