Panasonic KX-TG8421EB - Technical Descriptions; Block Diagrams and Circuit Operation

7
KX-TG8421E/KX-TG8422E/KX-TG8423E/KX-TG8424E/KX-TGA840E
4 Technical Descriptions
4.1. Block Diagram (Base Unit)
Analog
Front
End
T
o TEL_LINE
Bridge
Rect D3
D3
Hook Switch
Q4,Q5
Audio
Bell/Caller ID
Interface
CPU
18 16
23
20 21
19
24
BELL
HOOK
Off-Hook Line Voltage
25
A/D D/A
ADPCM
Codec Filter
DSP
Speech Encoding Speech Decoding
BMC
Burst Encoding
Burst Decoding
RF
PLL
5
3
77
75
9
10
EEPROM
SCL
SDA
57
58
44
To AC Adaptor
Limit
Resistor
Charge Detector
CHARGE CONTACT
(Optional)
VUNREG
3.0V
Reg.
IC1
2.4V
Reg.
Q9
1.8V
Reg.
Q8
3.0 V 2.4 V
1.8 V
BBIC
IC401
IC7
KX-TG8421/8422/8423/8424 BLOCK DIAGRAM (BASE UNIT)
MOD/DEMOD
Charge
Pump
43
2.5V
X
T
A
L
X
1
X1
1
0.3
68
M
H
z
IC
801
R
X
n
R
X
p
T
X
p
T
X
n
P
on
P
S
E
L
V
DD
-P
A
D
R
V
4
3
6
7
T
X
on
R
X
on
D
801
6
72
AN
T1
ANT2
9
8
AN
T1
AN
T2
R
F
P
A
AN
T1
AN
T2
78 73 74
80
L
1
L2
L1
L2
2
FLASH MEMORY
IC421
42
3.0V
54
55
56
53
T
A
M
-C
S
N
S
P
I-D
I
S
P
I-D
O
S
P
IC
L
K