Panasonic KX-FC968RU Service Manual ▷ View online
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KX-FC968RU-T
b. Redundancy Compression Process Coding Mode
This unit uses one-dimensional MH format.
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KX-FC968RU-T
6.6.2.
Modem Circuit Operation
The modem (IC3) has all the hardware satisfying the CCITT standards mentioned previously.
When the ASIC IC10 (61) is brought to a low level, the modem (IC3) is chip-selected and the resistors inside IC are selected by the
select signals from ASIC (IC10) ADR0-ADR4. The commands are written through the data bus, and all the processing is controlled
by the ASIC (IC10) according to CCITT procedures. The INT signal dispatched from IRQ (pins 100 of IC3) to ASIC (IC10) when the
transmission data is accepted and the received data is demodulated, the ASIC (IC10) implements post processing. This modem
(IC3) has an automatic application equalizer.
With training signal 1 or 2 during G3 reception, it can automatically establish the optimum equalizer. The modem (IC3) operates
using the 32.256 MHz clock (X1).
When the ASIC IC10 (61) is brought to a low level, the modem (IC3) is chip-selected and the resistors inside IC are selected by the
select signals from ASIC (IC10) ADR0-ADR4. The commands are written through the data bus, and all the processing is controlled
by the ASIC (IC10) according to CCITT procedures. The INT signal dispatched from IRQ (pins 100 of IC3) to ASIC (IC10) when the
transmission data is accepted and the received data is demodulated, the ASIC (IC10) implements post processing. This modem
(IC3) has an automatic application equalizer.
With training signal 1 or 2 during G3 reception, it can automatically establish the optimum equalizer. The modem (IC3) operates
using the 32.256 MHz clock (X1).
1. Facsimile Transmission
The digital image data on the data bus is modulated in the modem (IC3), and sent from pin 56 via, amplifier IC102 and the NCU
section to the telephone line.
Refer to Check Sheet for Signal Route (P.122).
section to the telephone line.
Refer to Check Sheet for Signal Route (P.122).
2. Facsimile Reception
The analog image data which is received from the telephone line passes through the NCU section and enters pin 47 of the
modem (IC3). The signals that enter pin 47 of the modem (IC3) are demodulated in the board to digital image signals, then
placed on the data bus.
placed on the data bus.
In this case, the image signals from the telephone line are transmitted serially. Hence, they are placed on the bus in 8 bit units.
Here, the internal equalizer circuit reduces the image signals to a long-distance receiving level.
This is designed to correct the characteristics of the frequency band centered around 3 kHz and maintain a constant receiving
sensitivity.
It can be set in the service mode.
Refer to Check Sheet for Signal Route (P.122).
This is designed to correct the characteristics of the frequency band centered around 3 kHz and maintain a constant receiving
sensitivity.
It can be set in the service mode.
Refer to Check Sheet for Signal Route (P.122).
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KX-FC968RU-T
6.7.
NCU Section
6.7.1.
General
It is composed of bell detection circuit, pulse dial circuit, line amplifier, sidetone circuits.
6.7.2.
Bell Detection Circuit
1. Circuit Operation
The signal waveform for each point is indicated below. The signal (low level section) input to pin 10 of BBIC IC4 on the digital
board.
TEL LINE
board.
TEL LINE
→ PC104 (1, 2 → 4) → IC4 (10)
6.7.3.
On/Off Hook Circuit
Normally (ON-HOOK condition), LINE RELAY (RLY101) is OFF. While OFF-HOOK, RLY101 turns ON. This LINE RELAY is
controlled by pin 83 of IC4 through the Q105.
ON-HOOK:
IC4 (83) Low Level
controlled by pin 83 of IC4 through the Q105.
ON-HOOK:
IC4 (83) Low Level
→ Q105 OFF → RLY101 OFF
OFF-HOOK:
IC4 (83) High Level
IC4 (83) High Level
→ Q105 ON → RLY101 ON
6.7.4.
Pulse Dial Circuit
The pulse dial is generated by operating the transistor Q105 while OFF-HOOK (RLY101 ON) condition.
Make state:
IC4 (83) High Level
Make state:
IC4 (83) High Level
→ Q105 ON → RLY101 ON
Break state:
IC4 (83) Low Level
IC4 (83) Low Level
→ Q105 OFF → RLY101 OFF
6.7.5.
Line Amplifier and Side Tone Circuit
1. Circuit Operation
The reception signal output from the line transformer T101 is input to pin (2) of IC101 via C118, R121 and then the signal is
amplified at pin (1) of IC101 and sent to the reception system at through the LPF.
amplified at pin (1) of IC101 and sent to the reception system at through the LPF.
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KX-FC968RU-T
6.7.6.
Calling Line Identification Circuit (RUSSIAN)
1. Function
The CID data is received after the bell rings while the phone is off-hook.The CID data consists of the dual tone signal
combined 700Hz, 900 Hz, 1100Hz and so on, which has unique frequency being different from usual dual tone signal.
Strictly speaking, 500Hz ACK signal is transmitted to the line to request the exchanger to send the Russian CID data. Then
the dual tone signal will be transmitted from the exchanger. The calling party’s number is recognized by the digital number
corresponding to the dual tone.
The data frame consists of 9 digits; start code, category code and 7 digits of calling party’s telephone number.
combined 700Hz, 900 Hz, 1100Hz and so on, which has unique frequency being different from usual dual tone signal.
Strictly speaking, 500Hz ACK signal is transmitted to the line to request the exchanger to send the Russian CID data. Then
the dual tone signal will be transmitted from the exchanger. The calling party’s number is recognized by the digital number
corresponding to the dual tone.
The data frame consists of 9 digits; start code, category code and 7 digits of calling party’s telephone number.
2. Circuit Operation:
The Russian CID signal from the telephone line is processed through the BBIC IC4 (cordless base). For further information
about Russian CID signal path, refer to Check Sheet for Signal Route (P.122)
about Russian CID signal path, refer to Check Sheet for Signal Route (P.122)
6.7.7.
Calling Line Identification Circuit (Western)
1. Function
This unit is compatible with the Caller ID service offered by your local telephone company. To use this feature, you must
subscribe to a Caller ID service. The data for the caller ID from the telephone exchange is sent during the interval between the
first and second rings of the bell signal. The data from the telephone exchange is a modem signal which is modulated in an
FSK (Frequency Shift Keying) format. Data “0” is a 1300 Hz sine wave, and data 1 a 2100 Hz sine wave.
There are two type of the message format which can be received:i.e.the single data message format and multiple data
message format.
The multiple data format allows to transmit the name and data code information in addition to the time and telephone number
data.
When there is multiple data in the unit, the name or telephone number are displayed.
subscribe to a Caller ID service. The data for the caller ID from the telephone exchange is sent during the interval between the
first and second rings of the bell signal. The data from the telephone exchange is a modem signal which is modulated in an
FSK (Frequency Shift Keying) format. Data “0” is a 1300 Hz sine wave, and data 1 a 2100 Hz sine wave.
There are two type of the message format which can be received:i.e.the single data message format and multiple data
message format.
The multiple data format allows to transmit the name and data code information in addition to the time and telephone number
data.
When there is multiple data in the unit, the name or telephone number are displayed.
2. Circuit Operation:
The caller ID signal input from TEL LINE is processed with BBIC (IC4).
Refer to Check Sheet for Signal Route (P.122) for the route of caller ID signal.
Refer to Check Sheet for Signal Route (P.122) for the route of caller ID signal.
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