System Outline
Service Manual
4-5
4.1.3 Line Interface Part
This is Connection Part between system and PSTN(Public Switched Telephone Network), and primary circuit is
usually located. Main functions are Line Interface, Telephone Connection and Line Condition Monitoring.
1 Telephone Line Connection
Modular Plug : RJ-11C
LIU PBA Modular Type : 623 PCB4-4
Line Code Length : 2500 50mm
Line Code Color : Black
ON HOOK state Characteristic
1) DC Resistance
DP Dial Mode (Direct Current 30mA) : 50 ~ 300ohm
DTMF Dial Mode (Direct Current 20mA) : 50 ~ 540ohm
2) Ring Sensitivity
Ring detection Voltage : 40Vrms 150Vrms (condition :Current=25mA,Frequency=15Hz)
product Margin : 30Vrms 150Vrms
Ring detection Frequency : 15.3Hz 68Hz (condition : Voltage=45Vrms,Current=25mA )
product Margin : 15Hz 70Hz
Ring detection Current : 20mA 100mA (condition : Voltage=40Vrms,Frequency=20Hz)
product Margin : over 15mA
3) False Ring Sound
Ring Frequency : 750 Hz + 1020 Hz
Ring interrupt Cycle : On/Off depending on input Ring Signal Cycle.
