Panasonic KX-FC268RU-T Service Manual ▷ View online
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KX-FC268RU-T
6.7.8.
Calling Line Identification Circuit (Russian CID)
The unit receives the calling number from the central office.
RCID contains numbers only.
When a telephone line is captured after the bell rings, 500Hz of ACK signal is sent to the line and the dual tone signal is output.
The calling number is recognized by the digit number corresponding to the dual tone.
RCID contains numbers only.
When a telephone line is captured after the bell rings, 500Hz of ACK signal is sent to the line and the dual tone signal is output.
The calling number is recognized by the digit number corresponding to the dual tone.
The outline of RCID TX/RX is shown below.
1. Receiving Signal
Receiving signal route is same as “ICM Record signal”.
2. ACK signal
ACK signal route is same as “DTMF for TEL LINE signal“.
Refer to Check Sheet for Signal Route (P.127) for signal route.
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KX-FC268RU-T
6.8.
ITS (Integrated Telephone System) and Monitor Section
6.8.1.
Speakerphone Circuit
Function
This circuit controls the automatic switching of the transmitted and received signals, to and from the telephone line, when the
unit is used in the hands-free mode.
unit is used in the hands-free mode.
Circuit Operation
The speakerphone can only provide a one-way communication path.
In order words, it can either transmit an outgoing signal or receive an incoming signal at a given time, but cannot do both simul-
taneously. Therefore, a switching function is necessary to control the flow of the outgoing and incoming signals.
This switching function is contained in IC4 and consists of voice detector, TX attenuator, RX attenuator, comparator and attenu-
ator control. The function analyzes whether the TX (Transmit) or the RX (receiver) signal is louder, and then it processed the sig-
nal such that the louder signal is given precedence. The vice detector provides the attenuator control corresponding to the TX
signal. The comparator receives a TX and RX signals to the attenuator control corresponding to the RX signal. The attenuator
control provides a control signal to the TX and the RX attenuator to switch the appropriate signals ON and OFF. The attenuator
control also detects the level of the volume control to automatically adjust for changing ambient conditions.
In order words, it can either transmit an outgoing signal or receive an incoming signal at a given time, but cannot do both simul-
taneously. Therefore, a switching function is necessary to control the flow of the outgoing and incoming signals.
This switching function is contained in IC4 and consists of voice detector, TX attenuator, RX attenuator, comparator and attenu-
ator control. The function analyzes whether the TX (Transmit) or the RX (receiver) signal is louder, and then it processed the sig-
nal such that the louder signal is given precedence. The vice detector provides the attenuator control corresponding to the TX
signal. The comparator receives a TX and RX signals to the attenuator control corresponding to the RX signal. The attenuator
control provides a control signal to the TX and the RX attenuator to switch the appropriate signals ON and OFF. The attenuator
control also detects the level of the volume control to automatically adjust for changing ambient conditions.
6.9.
Transmitter / Receiver (Cordless)
Base Unit and Cordless Handset mainly consist of RF Module and DECT BBIC.
Base Unit and Cordless Handset transmit/receive voice signal and data signal through the antenna on carrier frequency.
Base Unit and Cordless Handset transmit/receive voice signal and data signal through the antenna on carrier frequency.
6.9.1.
Transmitter Block
The voice signal input from the TEL LINE interface goes to RF Module (IC28) through DECT BBIC (IC4).
The voice signal passes through the analog part of IC4 where it is amplified and converted to a digital audio stream signal. The
burst switch controller processes this stream performing encryption and scrambling, adding the various other fields to produce
the GAP (Generic Access Profile) standard DECT frame, assigning to a time slot and channel etc.
In IC28, the carrier frequency is changing, and frequency modulated RF signal is generated and amplified, and radiated from
antenna. Cordless Handset detects the voice signal or data signal in the circuit same as the following explanation of Receiver
Block.
The voice signal passes through the analog part of IC4 where it is amplified and converted to a digital audio stream signal. The
burst switch controller processes this stream performing encryption and scrambling, adding the various other fields to produce
the GAP (Generic Access Profile) standard DECT frame, assigning to a time slot and channel etc.
In IC28, the carrier frequency is changing, and frequency modulated RF signal is generated and amplified, and radiated from
antenna. Cordless Handset detects the voice signal or data signal in the circuit same as the following explanation of Receiver
Block.
6.9.2.
Receiver Block
The signal of 19.2 MHz band (18.81792 MHz ~ 18.97344 MHz) which is input from antenna is input to IC28.
In IC28, the signal of 19.2 MHz band is down converted to 864 kHz signal and demodulated, and goes to IC4 as GAP (Generic
Access Profile) standard DECT frames. It passes through the decoding section burst switch controller where it separates out the
frame information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is turned
back into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.
In IC28, the signal of 19.2 MHz band is down converted to 864 kHz signal and demodulated, and goes to IC4 as GAP (Generic
Access Profile) standard DECT frames. It passes through the decoding section burst switch controller where it separates out the
frame information and performs de-encryption and de-scrambling as required. It then goes to the DSP section where it is turned
back into analog audio. This is amplified by the analog front end, and goes to the TEL LINE Interface.
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KX-FC268RU-T
6.10. Operation Board Section
The unit consists of a LCD (Liquid crystal display), KEYs and LEDs (light-emitting diodes). They are controlled by the Gate Array
(IC301) and ASIC (IC10: on the DIGITAL BOARD). The key matrix table is shown below.
(IC301) and ASIC (IC10: on the DIGITAL BOARD). The key matrix table is shown below.
CN301
CN206
IC10
ASIC
LCD MODULE
GATE ARRAY
IC301
CN302
DOCUMENT TOP SENSOR
DOCUMENT SET SENSOR
DOCUMENT SET SENSOR
AUTO ANSWER
8x5
KEYS
MATRIX
KEYS
MATRIX
DIGITAL BOARD
OPERATION BOARD
XLED9, 10
LED2
KIN0~7
KSL0~4
KX-FC268RU-T : OPERATION BOARD BLOCK DIAGRAM
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KX-FC268RU-T
6.11. LCD Section
The Gate Array (IC301) works only for writing the ASCII code from the data bus (D4~D7). V0 is supplied for the crystal drive.
R310, R311 and R312 are density control resistors.
Consequently, in this unit, the timing (positive clock) is generated by the LCD interface circuitry in the gate array (IC301).
R310, R311 and R312 are density control resistors.
Consequently, in this unit, the timing (positive clock) is generated by the LCD interface circuitry in the gate array (IC301).
DIsplay mode
Density
Normal
Dark
2 lines (X1.0)
LED1 (IC301-22pin)
H
L
XL14 (IC301-20pin)
Hi-Z
L
XL15 (IC301-21pin)
L
L
1 line (X1.5)
LED1
H
H
XL14
Hi-Z
Hi-Z
XL15
Hi-Z
L
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