Panasonic KX-TDA50 Installation Manual page 57

Outside Installation
Surge Protector
CO Line
Terminal
Board
Extn.
SLT
If you install an extension outside of the building, the following precautions are recommended:
a.
Install the extension wire underground.
b.
Use a conduit to protect the wire.
Note
The surge protector for an extension and CS is different from that for a CO line.
Installation of a Ground Rod
Surge Protector
CO Line
Grounding
Wire
(Underground)
(Main Building)
CO Line
Hybrid
IP-PBX
Extn.
Extn.
PT CS
Hybrid
IP-PBX
Ground Rod
2.2 Installation of the Hybrid IP-PBX
(Another Building)
SLT
PT
Extn.
CS
Surge
Protector
Ground
Extn.: Extension Line
Installation Manual 57