Panasonic KX-FC965RU Service Manual ▷ View online
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KX-FC965RU-T
b. Redundancy Compression Process Coding Mode
This unit uses one-dimensional MH format.
This unit uses one-dimensional MH format.
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KX-FC965RU-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 108 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 (IC505) 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 108 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 (IC505) 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 69 via Analogue SW IC509, ampli-
fier IC102 and the NCU section to the telephone line.
fier IC102 and the NCU section to the telephone line.
Refer to Check Sheet for Signal Route (P.134).
2. Facsimile Reception
The analogue image data which is received from the telephone line passes through the NCU section and enters pin 60 of the
modem (IC3). The signals that enter pin 60 of the modem (IC3) are demodulated in the board to digital image signals, then
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 about 3 kHz and maintain a constant receiving
sensitivity. It can be set in the service mode.
modem (IC3). The signals that enter pin 60 of the modem (IC3) are demodulated in the board to digital image signals, then
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 about 3 kHz and maintain a constant receiving
sensitivity. It can be set in the service mode.
Refer to Check Sheet for Signal Route (P.134).
3. DTMF Transmission (Monitor tone)
The DTMF signal generated in the modem (IC3) is output from pin 69, and is then sent to the circuit on the same route as
used for facsimile transmission.
used for facsimile transmission.
Refer to Check Sheet for Signal Route (P.134).
(DTMF Monitor Tone)
Refer to Check Sheet for Signal Route (P.134).
Refer to Check Sheet for Signal Route (P.134).
4. Call Tone Transmission
This is the call signal which is generated in the ASIC (IC10) and sent to the speaker.
Refer to Check Sheet for Signal Route (P.134).
5. Busy/Dial Tone Detection
The path is the same as FAX receiving. When it is detected, the carrier detect bit of the resistor in the modem (IC3) becomes
1, and this status is monitored by the ASIC (IC10).
1, and this status is monitored by the ASIC (IC10).
6. Caller ID Detection
The caller ID signal which is received from the telephone line/passes through IC500 pin (6-7). And it enters pin 101 of the
BBIC (IC4).
BBIC (IC4).
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KX-FC965RU-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 con-
trolled by pin 83 of IC4 through the Q105.
ON-HOOK:
IC4 (83) Low Level
trolled 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
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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 IC104 via C118, R121 and then the signal is
amplified at pin (1) of IC104 and sent to the reception system at through the LPF.
amplified at pin (1) of IC104 and sent to the reception system at through the LPF.
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