Read Panasonic KX-TS85GB / KX-TS85GW Service Manual online
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1
2
3
4
5
6
7
8
9
10
11
12
G
F
E
D
C
B
A
H
KX-TS85GB/KX-TS85GW
KX-TS85GB/KX-TS85GW
BLOCK DIAGRAM
Circuit Diagram
•¡
TONE DIAL CIRCUIT
Function:
The tone dialing circuit consists of a DTMF (Dual Tone Multi Frequency) signal generator (outputted from Pin 12 of the
IC1) for tone dialing, and also a circuit for outputting the signal to line.
The DTMF circuit identifies inputs from the 12 keys (1,2,3,4,5,6,7,8,9,0,
The tone dialing circuit consists of a DTMF (Dual Tone Multi Frequency) signal generator (outputted from Pin 12 of the
IC1) for tone dialing, and also a circuit for outputting the signal to line.
The DTMF circuit identifies inputs from the 12 keys (1,2,3,4,5,6,7,8,9,0,
•–
and #) by means of a total of seven frequencies,
that is four low frequencies (Low group) and three high frequencies (High group).
Circuit Description:
When a dial key is pressed, a DTMF signal is output from Pin 12 of IC1 as an analog synthetic wave.
The signal flow to the line is as follows.
Pin 12 of IC1
When a dial key is pressed, a DTMF signal is output from Pin 12 of IC1 as an analog synthetic wave.
The signal flow to the line is as follows.
Pin 12 of IC1
•¨
Q6
•¨
R18
•¨
Q4
•¨
Tel Line.
The DTMF signal is sent to the line via the following path. Q6 is an amplifier which is used to output the signal to line.
Following is the signal flow used to output the DTMF signal from the handset as a monitor tone when a dial key is
pressed.
Pin 21 of IC1
Following is the signal flow used to output the DTMF signal from the handset as a monitor tone when a dial key is
pressed.
Pin 21 of IC1
•¨
R32
•¨
C28
•¨
Handset Speaker.
The signal combination and frequency correspoonding the each dial key is shown in p23.
Note:
The circuit diagram may be modified at any time with the development of new technology.
The circuit diagram may be modified at any time with the development of new technology.
CIRCUIT OPERATIONS
•¡
TELEPHONE LINE INTERFACE and PULSE DIAL CIRCUIT
When the hook switch S1 is ON (off-hook), the circuit is closed, and current is supplied to the base of Q3 via the diode
bridge D4 and Q3 is On
bridge D4 and Q3 is On
•¨
Q4 is ON (OFF-HOOK condition).
Q4 and Q3 are the dial pulse generating circuits, and are driven by the DIALER (IC1), when the DIALER Pin 2 of IC1 is
LOW
LOW
•¨
Q3 is OFF and Q4 is OFF. (break)
If port Pin 2 is HIGH
•¨
Q3 is ON
•¨
Q4 is ON. (make)
MIC
SPEAKER
Key
Board
Switch
Board
Switch
EEPROM
DIALER
DTMF
Output and Control
Circuit
SP Amp
Q3,Q4
Q1,Q2
Q6
D4
Dial Pulse
Switch
and
On/Off
Control
Switch
and
On/Off
Control
Diode
Bridge
C1
C2
R1
R2
D1
IC1
H/S
MIC
SPEAKER
Handset
Amp
Receiving
Transmitting
and
Address
Signal
Amp
Receiving
Transmitting
and
Address
Signal
T
R
S1
Transmit
Amp
Diode
Bridge
DC-DC
CONVERTER
C45
IC2
Tone
Ringer
Circuit
R1
R3
R4
D1
R10
R11
R13
R15
R14
SI-2
R16
Q4
D7
R19
R20
R21
R7
C10
R9
Q2
Q1
D6
L2
D8
C14
D5
POS1
ZNR2
JACK1
R12
R5
R18
C1
R2
D2
D3
D15
D14
C2
C6
D4
3
4
2
1
C7
C5
C8
C11
C13
2
3
4
5
B
Ring
Tip
A
SI-1
Pin 2 of
IC1
IC1
Q3
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