DOWNLOAD Panasonic KX-TG2521RUT / KX-TGA251RUT Service Manual ↓ Size: 2.54 MB | Pages: 77 in PDF or view online for FREE

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There are several types of PbF solder available commercially. While this product is manufactured using Tin, Silver, and Copper
(Sn+Ag+Cu), you can also use Tin and Copper (Sn+Cu) or Tin, Zinc, and Bismuth (Sn+Zn+Bi). Please check the manufacturer’s
specific instructions for the melting points of their products and any precautions for using their product with other materials. 
The following lead free (PbF) solder wire sizes are recommended for service of this product: 0.3 mm, 0.6 mm and 1.0 mm.

When discarding P. C. Board, delete all personal information such as telephone directory and caller list or scrap P. C. Board.

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• Design and specifications are subject to change without notice.

• Operation range: Up to 300 m outdoors, Up to 50 m indoors, depending on the condition.
• Analog telephone connection: Telephone Line

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Analog

Front

End

T

o TEL_LINE

Bridge

Rect

 D3D3

Hook Switch

Q3,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)

IC2

Q9

Q8

2.4V

Reg.

1.8V

Reg.

3.0 V

2.4 V

1.8 V

BBIC

KX-TG2521 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

R

X

n

R

X

p

T

X

p

T

X

n

P

on

P

S

E

L

V

D

D

-P

A

D

R

V

4

3

6

7

T

X

on

R

X

on

D801

6

72

AN

T1

AN

T2

9

8

AN

T1

ANT2

R

F

 P

A

ANT1

AN

T2

78

73

74

80

L

1

L

2

D

C

P

D

C

M

2

FLASH MEMORY

IC421

42

3.0V

54 
55

56 
53

TA

M-C

Sn

SP

I-DI

SP

I-DO

SP

ICL

K

IC3

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Base Unit consists of the following ICs as shown in Block Diagram (Base Unit) (P.7).

• DECT BBIC (Base Band IC): IC7

- Handling all the audio, signal and data processing needed in a DECT base unit
- Controlling the DECT specific physical layer and radio section (Burst Module Controller section)
- ADPCM code filter for speech encoding and speech decoding (DSP section)
- Echo-cancellation and Echo-suppression (DSP section)
- Any tones (tone, sidetone, ringing tone, etc.) generation (DSP section)
- DTMF receiver (DSP section)
- Clock Generation for RF Module
- ADC, DAC, timer, and power control circuitry
- PLL Oscillator
- Detector 
- Compress/Expander
- First Mixer
- All interfaces (ex: RF Power Amp, EEPROM, LED, Analog Front End, etc.)

• RF Power Amp.: IC801

- Amplifier for transmission and reception

• EEPROM: IC401

- Temporary operating parameters (for RF, etc.)

• FLASH MEMORY: IC421

- Voice Prompt (TAM) D/L Area
- ICM/OGM Recording Area

• Additionally,

- Power Supply Circuit (+3.0 V, +2.4 V, +1.8 V output)
- Crystal Circuit (10.368 MHz)
- Charge Circuit
- Telephone Line Interface Circuit