Section 1.4, Options; Pay Tone Card (Kx-Td189); 2-Isdn S0 Line Unit (Kx-Td280); Section 2.4, Installation Of Optional Cards And Units - Panasonic KX-TD816CE Installation Manual

1.4 Options

Pay Tone Card (KX-TD189)

2-ISDN S0 Line Unit (KX-TD280)

2.4 Installation of Optional Cards and Units

2-ISDN S0 Line Unit Connection

6
Supports the Pay Tone service of the central office. While having
a conversation with an outside party, your central office generates
the pay tone so that the counting for fee starts for the call.
One KX-TD280 can be installed per system.
2 ISDN S0 lines
can be added.
To add two ISDN S0 lines, use the optional 2-ISDN S0 Line Unit
(KX-TD280). This unit can be installed in any of the expansion
areas provided on the front of the main unit.
The following procedures can be used to install the 2-ISDN S0 Line
Unit (KX-TD280). System programming is required for unit
location identification.
Default KX-TD816: bottom = 4-CO Line Unit,
KX-TD1232: bottom = 4-CO Line Unit,
D816 D816
DIGITAL SUPER HYBRID SYSTEM
top = 8-Station Line Unit
middle and top = 8-Station Line Unit
2 ISDN S0 lines
can be added.