Panasonic KX-MB1900UCB / KX-MB2020UCB (serv.man2) Service Manual ▷ View online
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KX-MB1900UCB/KX-MB2020UCB
6.4.
NCU Section (KX-MB2020 ONLY)
6.4.1.
General
This section is the interface between the telephone line and external telephone. It is composed of an EXT. TEL line relay (RLY100),
bell detection circuit, TAM interface circuit and line amplifier.
bell detection circuit, TAM interface circuit and line amplifier.
6.4.2.
EXT. TEL. Line Relay (RLY100)
1. Circuit Operation
Normally, this relay switches to the external telephone side and switches to the open side while OFF-HOOK.
IC300 (R33) High Level
IC300 (R33) High Level
→Q100 ON→RLY100 (ON)
6.4.3.
Bell Detection Circuit
1. Circuit Operation
The signal waveform is indicated below. The bell signal input to IC101 and ring detected signal output from pin 15 of IC100.
IC300 monitor this signal and judged as bell.
TEL LINE
IC300 monitor this signal and judged as bell.
TEL LINE
→IC101 (8,9 - 5,6)→IC100 (9,10 - 15)→IC300(AA25)
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KX-MB1900UCB/KX-MB2020UCB
6.4.4.
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. Circuit Operation
The caller ID signal input from TEL LINE is processed with Soc (IC300).
TEL LINE
TEL LINE
→IC101 (3 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
6.4.5.
Remote FAX Activation Circuit
1. Function
Another telephone connected to same line activates the unit to the FAX mode by using a DTMF signal.
2. Signal Path
TEL LINE
→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
6.4.6.
TAM Interface Circuit
This circuit is to switch between FAX receiving and the external TAM’s message recording automatically.
For details, please refer to TAM Interface Section (P.31).
For details, please refer to TAM Interface Section (P.31).
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KX-MB1900UCB/KX-MB2020UCB
6.5.
ITS (Integrated telephone System) and Monitor Section (KX-MB2020
ONLY)
ONLY)
6.5.1.
General
The general ITS operation is performed by IC200 which has a handset circuit. The alarm tone, the key tone, and the beep are
output from Soc IC300.
output from Soc IC300.
6.5.1.1.
Telephone Monitor
1. Function
This is the function when you are not holding the handset and can hear the caller’s voice from the line.
2. Circuit Operation
(Telephone Monitor Signal Path)
Signals received from the telephone line are output through at the speaker via the following path.
Signals received from the telephone line are output through at the speaker via the following path.
3. Signal Path
TEL LINE
→D103→Q104→C106→IC101(3-5,6)→IC100(9,10-5)→IC300(AD26-AB24)→IC200(4-1)→IC202(2-1)→IC204(4-
5,8)
→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
6.5.1.2.
Monitor Circuit
1. Function
This circuit monitors various tones, such as (1) DTMF tone, (2) Alarm/Beep/Key tone/Bell.
2. Signal Path
a. DTMF MONITOR
(Speaker Operation)
IC300(AB24)
IC300(AB24)
→IC200(4-1)→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
(Handset Operation)
IC300(AB24)
IC300(AB24)
→IC200(4-16)→IC203(4-8)→CN200(7,8)→CN58(7,8)→HANDSET SPEAKER
b. ALARM/BEEP/KEY TONE/BELL
IC300(B20)
→IC202(2-1)→IC204(4-5,8)→CN200(1,2)→CN58(1,2)→CN57(1,2)→SPEAKER
6.5.1.3.
TAM Interface Section
1. Function
When TAM is connected to this unit, the unit receives documents for FAX calls or the external TAM records a voice message
automatically.
automatically.
2. Circuit Operation
The TAM INTERFACE circuit consists of Soc(IC300) to detect the other party CNG signal, and RLY100 to separate EXT.TAM.
a. CNG signal detection circuit
The CNG signal from the other party’s FAX is detected in Soc IC300
(Signal path)
TEL LINE
(Signal path)
TEL LINE
→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
b. Remote receiving
This is the parallel-connected DTMF signal for the TEL or EXT.TEL mode between T and R. When the other party is a
FAX, the unit switches to FAX receiving.
(Signal Path)
TEL LINE
FAX, the unit switches to FAX receiving.
(Signal Path)
TEL LINE
→IC101 (8,9 - 5,6)→IC100 (9,10 - 5)→IC300(AD26)
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KX-MB1900UCB/KX-MB2020UCB
6.6.
CIS Control Section
The scanning block of this device consists of a control circuit and a CIS (contact image sensor), and AFE(Analog Front End) include
A/D Converter.
A/D Converter.
When an original document is inserted and the start button pressed, pin A3 of IC300 goes to a low level and the transistor Q518
turns on.
This applies voltage to the CIS. The CIS is driven by each of the CCDSH , CCDCLK signals output from IC300, and the original
image illuminated by the LED to output an analog image signal.
The analog image signal is input to the AFE on VINP(20pin of IC503) and converted into 16-bit data by the A/D converter inside
IC503. Then this signal undergoes digital processing in order to obtain a high-quality image.
turns on.
This applies voltage to the CIS. The CIS is driven by each of the CCDSH , CCDCLK signals output from IC300, and the original
image illuminated by the LED to output an analog image signal.
The analog image signal is input to the AFE on VINP(20pin of IC503) and converted into 16-bit data by the A/D converter inside
IC503. Then this signal undergoes digital processing in order to obtain a high-quality image.
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