LG GDK-20W User Manual

GDK-20W DIGITAL WIRELESS KEY TELEPHONE SYSTEM     
 

 

 
 
 
 
 

 
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. 
 
  
 
 
 
 
 
 
 
 
  
    
 

 
 
 
 
 
 
 

 
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