Panasonic KX-TDA1178X (serv.man5) Service Manual ▷ View online
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KX-TDA1178X
5.2.10. Power Failure Switch Feature
2 out of 24 lines have switching relays (RL200A-B) installed in order to enable the outside call during a power failure. The line con-
nected to the outside call card will be directly connected to the CN201 located in forward part of the board via a 4-conductor TEL
cord. In the normal operation mode, it breaks the power failure switching relay, and during a power failure, it makes the power fail-
ure switching relay to initiate Power failure direct connection mode.
nected to the outside call card will be directly connected to the CN201 located in forward part of the board via a 4-conductor TEL
cord. In the normal operation mode, it breaks the power failure switching relay, and during a power failure, it makes the power fail-
ure switching relay to initiate Power failure direct connection mode.
5.2.11. Bell Signal Generator and Transmission
In ringing mode, the ringing DC offset and the ringing signal are summed digitally within CODEC in accordance with the pro-
grammed values.
This signal is then converted to an analog signal and applies to the SLIC.
The SLIC amplifies the signal and supplies the line with 65 Vrms.
The bell signal is generated with +80V(VHR) and -30V (VBATL) supplied to SLIC.
grammed values.
This signal is then converted to an analog signal and applies to the SLIC.
The SLIC amplifies the signal and supplies the line with 65 Vrms.
The bell signal is generated with +80V(VHR) and -30V (VBATL) supplied to SLIC.
5.2.12. Message Waiting Generator and Transmission
In Message Waiting (MW) he MW signal is summed digitaly within CODEC in accordance with the programmed values.
The SLIC amplifies the signal and supplies the line with 90V.
The MW signla is generated with +80V (VHR) and -30V (VBATL) supplied SLIC.
The SLIC amplifies the signal and supplies the line with 90V.
The MW signla is generated with +80V (VHR) and -30V (VBATL) supplied SLIC.
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KX-TDA1178X
5.2.13. EXT-CID Transmission
This CODEC (IC201A-X) generates the extension Caller ID signals (FSK signal) with the CPU control.
The data flow is shown below.
The data flow is shown below.
5.2.14. Power Supply Voltage Generator
• Block Diagram
The input from the main power supply is in 2 voltage levels: +15V, +40V.
Since the voltage levels: +15V, +3.3V, +80V, -30V are required onboard, voltage levels are generated onboard as written below.
Since the voltage levels: +15V, +3.3V, +80V, -30V are required onboard, voltage levels are generated onboard as written below.
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KX-TDA1178X
• Protection of 3.3V output
The protection circuit consists of an output short protection and an overvoltage protection.
When an output of power supply is short, IC1 works to stop the output as the output short protection.
When +3.3V output become overvoltage caused by Q4 short, it is detected by D7. Q3 is cut by Q2 to shut down the input power
supply as the overvoltage protection.
When an output of power supply is short, IC1 works to stop the output as the output short protection.
When +3.3V output become overvoltage caused by Q4 short, it is detected by D7. Q3 is cut by Q2 to shut down the input power
supply as the overvoltage protection.
• +80V/-30V Converter
Q809 is switched ON with input voltage of 28V to supply 15V to control circuits in all converters. Then all converters start up. Cir-
cuit configuration of -30V converter is same as +80V.
cuit configuration of -30V converter is same as +80V.
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KX-TDA1178X
6 Location of Controls and Components
6.1.
Names and Locations
Overview
Inside View
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