LG GDK-20W - Manual (Page 33)

GDK-20W DIGITAL WIRELESS KEY TELEPHONE SYSTEM
35
Alarm Detect Port Wiring
One external alarm detect input port is provided from the TERMINAL BLOCK CN22(pin#3,4) of the MBU. This port is
used for notify to extensions when the external switch on/off. The connection example is shown in Figure 3.5.3.
Close or open detection is programmable by administration programming.
Figure 3.5.3 External Switch Wiring Example
Ferrite Core Installation
A ferrite core is provided in the package of the KSU. Ferrite core should be installed when wiring MBU, CO board, and
WTIB.
Ferrite core is used to proof the EMI and to protect the system from the impulse noises.
Ferrite core should be installed on signal wires as Figure 3.5.4 Ferrite core on signal wires.
External Switch
Pin #3 of CN22
Pin #4 of CN22