Panasonic KX-NCP1174XJ (serv.man2) Service Manual ▷ View online
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KX-NCP1174XJ
5.2.5.
Power Supply
A constant-current power supply in HIC provides +30V, ring side 0V grounding to SLC. The maximum feeding current is 30mA.
5.2.6.
Dial Pulse Detection
When a telephone initiates pulse dialing, this feature detects the pulse-dialing signal.
When the telephone initiates dialing, changes in voltage is detected by the RING terminal in HIC, and this information is transmitted
to the HOOK terminal (Example: 3-pin IC200A) as Make=L/Break=H signal. This digital signal is received by CODEC IC (Example:
35-pin IC201) and recognized as dialing signal. Both 10pps and 20pps can be received. The dialing speed is analyzed by software.
When the telephone initiates dialing, changes in voltage is detected by the RING terminal in HIC, and this information is transmitted
to the HOOK terminal (Example: 3-pin IC200A) as Make=L/Break=H signal. This digital signal is received by CODEC IC (Example:
35-pin IC201) and recognized as dialing signal. Both 10pps and 20pps can be received. The dialing speed is analyzed by software.
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KX-NCP1174XJ
5.2.7.
Hook Detection
The off-hook status is detected when the telephone is off-hook. When a telephone is off-hook, change in voltage is detected by the
RING terminal in HIC, and this information is transmitted to the HOOK terminal (Example: 9-pin IC200A) as OFF-HOOK=L/ON
HOOK=H signal. This digital signal is received by CODEC IC (Example: 35-pin IC201) and recognized as off-hook signal. The off-
hook status is analyzed by software.
RING terminal in HIC, and this information is transmitted to the HOOK terminal (Example: 9-pin IC200A) as OFF-HOOK=L/ON
HOOK=H signal. This digital signal is received by CODEC IC (Example: 35-pin IC201) and recognized as off-hook signal. The off-
hook status is analyzed by software.
5.2.8.
Ring Trip Feature
When the BELL signal is sent out, the off-hook signal from a SLT is detected, and then it breaks the BELL relay.
When the handset of a ringing telephone is picked up, a DC loop is formed in the sequence of "Original bell signal", "Internal electri-
cal resistance of a telephone", "Intercom bell load resistance" (R203A-P:1K
When the handset of a ringing telephone is picked up, a DC loop is formed in the sequence of "Original bell signal", "Internal electri-
cal resistance of a telephone", "Intercom bell load resistance" (R203A-P:1K
Ω), and then "Ground" (Since DC30V superimposed in
the BELL signal). As a result of this, a voltage rise occurs in Intercom bell load resistance" (R203A-P:1K
Ω) in the intercom circuit,
and a voltage is placed on the 9-pin RING terminal. This change in voltage turns off the driver transistor of the BELL relay in HIC,
and it breaks the BELL relay.
and it breaks the BELL relay.
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KX-NCP1174XJ
5.2.9.
Surge Protection
ZNRs installed between T and R, and between T or R and FG protect from extraneous surge.
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KX-NCP1174XJ
5.2.10. Bell Signal Generator
Bell signal for ringing an SLT is generated by amplifying the 20 or 25Hz square wave provided from MPR card to AC75Vrms
onboard. The SW power supply in the BELL circuit generates between +160V and -100V of voltage by switching the +40V from the
power source at 125KHz frequencies. The Bell signal picks up the square wave provided from MPR via a photocoupler, and it is
transformed into SIN wave, then amplified to AC75Vrm bell signal by the amplitude between +160V and -100V of voltage (Mainly
+30Vdc) produced by SW power supply.
When the Bell signal is not needed, bell signal voltage generating circuit can be turned off by transmitting H signal from P21 port
(BELL CNT) of ASIC to reduce the power consumption.
onboard. The SW power supply in the BELL circuit generates between +160V and -100V of voltage by switching the +40V from the
power source at 125KHz frequencies. The Bell signal picks up the square wave provided from MPR via a photocoupler, and it is
transformed into SIN wave, then amplified to AC75Vrm bell signal by the amplitude between +160V and -100V of voltage (Mainly
+30Vdc) produced by SW power supply.
When the Bell signal is not needed, bell signal voltage generating circuit can be turned off by transmitting H signal from P21 port
(BELL CNT) of ASIC to reduce the power consumption.
5.2.11. Bell Signal Transmission
AC 75Vrms bell signal generated onboard is transmitted to the individual port, then control the bell ON/OFF by making a bell relay
in each port (Bell signal ON) and by breaking it (Bell signal OFF).
The 16 ports do not ring simultaneously. They are divided into 4 layers to control ON/OFF. They are divided in to following 4 groups
(The ports in the same group ring simultaneously.): "1, 5, 9, 13", "2, 6, 10, 14", "3, 7, 11, 15" and "4, 8, 12, 16".
in each port (Bell signal ON) and by breaking it (Bell signal OFF).
The 16 ports do not ring simultaneously. They are divided into 4 layers to control ON/OFF. They are divided in to following 4 groups
(The ports in the same group ring simultaneously.): "1, 5, 9, 13", "2, 6, 10, 14", "3, 7, 11, 15" and "4, 8, 12, 16".
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