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10

• Bell signal detection
• CLIP signal detection
• ON/OFF hook and pulse dial circuit

In standby mode,Q111/Q115 is open to cut the DC Loop current and decrease the ring load.
When ringing voltage appears at the TIP and RING, AC ring voltages transferred as followings;
CLIP signal detection

TIP 

→ C181 → R182 → R185 → IC501(26)(BBIC-CIDINn)

RING 

→ C191 → R192 → R195 → IC501(27)(BBIC-CIDINp)

TIP 

→ C181 → R182 → C184 → R186 → C187 → IC501(30)(BBIC-RINGING)

When power line failure (Because this case is no power to IC501)
TIP 

→ C164 → D161(2) → D161(1) →  IC101(1:5) → R167 → RINGERP

RING 

← D161(3) ← D161(4) ← Q162(c:e) ← IC101(2:8) ← RINGERM

ON hook:
Q111/Q115 is open to cut the DC loop current and voice signal, caused by the following control:
Hook switch (between hook2-4 and hook2-6) is opened and IC501(29)(Hook CTRL) is Low, (and Q114 is open), then Q112 is
OFF,so Q111/115 is OPEN
OFF hook:
Q111/Q115 is ON to make the DC loop current and be possible to transfer voice signal, caused by the following control:
Hook switch (between hook2-4 and hook2-6) make and IC501(29)(Hook CTRL) is High. (and Q114 is open), then Q112 is ON.

The audio signal from Mic (for SP-phone and Corded Handset) is converted from Analog to digital in TAM companion IC(IC201),
then is transfered to BBIC(IC501) through PCM interface.
In BBIC(IC501), these data is converted to Analog, then send out tel line through tel line interface.
On the other hand, the audio signal from tel line is converted from Analog to digital in BBIC(IC501), then is transfered to TAM
companion IC(IC201) through PCM interface.
In TAM companion IC(IC201) ,these data is converted to Analog, then sound out from speaker.

On the recorded and replay TAM data, as following.
On recording sound, the audio signal from the tel line is converted to digital data in BBIC, then is transfered to TAM companion
IC through SPI2 interface and compressed. This compressed data re-transfer to BBIC, then BBIC transfer these data to Flash-
memory(IC541)  through SPI interface. On replaying the recorded TAM data, the compressed data in Flash-memory is transferd
to BBIC through SPI interface. Then BBIC transfer these data to TAM companion IC through SPI2 interface to decompress
these data.TAM companion IC send back the decompress data to BBIC. BBIC transfer them to TAM companion IC through PCM
interface, finally these data is coverted to Analog signal, then sound out Speaker.
Refer to the fig.2.

<Fig.2>

11

BBIC(IC501) inclueds the RF transceiver circuit. (LNA,Mixer, IF filter, modulator/Demodulator,PLL, VCO etc).
This RF transceiver is interfaced  with Power-AMP(IC801) and Antenna circuit.

During pulse dialling the hookswitch (Q3, Q4) is used to generate the pulses using the HOOK control signal, which is set high
during pulses. To force the line impedance low during the “pause” intervals between dial pulses, the PULSE_DIAL signal turns
on Q2.

12

SPEAKER

RECEIVER

MIC

CHARGE

CIRCUIT

Q4, Q9, R7Q4,

Q9,

R7

CHARGE

CONTACTS

CHARGE(+)

CHARGE(-)

CHARGE_CTRL

CHARGE

EEPROM

SCL

SDA

BATTERY

TERMINAL

D7

VBAT

J1

J2

1.8 V

Q2

1.8 V

LCD

CD

RESET

CSB

SDA

 SCL

CPU

Analog

Front

End

D/A

A/D

33

35

15

16

19

20

32

31

57

58

 36

13

43

42

63

54

55

66

ADPCM

Codec

Filter

DSP

Speech

Decoding

Speech

Encoding

BMC

Burst

Decoding

RF PA

ANT1

Burst

Encoding

RF

PLL

MOD/DEMOD

5

3

4

3

6

7

8

9

2

77

78

75

RXn

RXon

ANT1

DA801

RXp

TXp

TXn

Pon

PSEL

TXon

VDD-PADRY

9

10

XTAL

X1

10.368

MHz

BATTERY

44

ON SWITCH

KEYPAD

Charge

Pump

ROWS

COLUMNS

CP3.0V

CP4.0V

48, 49, 50, 51

22, 23, 24, 25, 26

BBIC

 56

LCD-BACK  LIGHT

KEY   LED

BELL  LED

52

68

73

74

80

LDO_CTRL

KX-TGA641 BLOCK DIA

GRAM (CORDLESS HANDSET)

13

Cordless Handset consists of the following ICs as shown in Block Diagram (Cordless Handset) (P.12).

• DECT BBIC (Base Band IC): IC1

- All data signals (forming/analyzing ACK or CMD signal)
- All interfaces (ex: Key, Detector Circuit, Charge, DC/DC Converter, EEPROM, LCD, RF Power Amp.)
- PLL Oscillator
- Detector
- Compress/Expander
- Reception

• RF Power Amp: IC801

- Amplifier for transmission

• EEPROM: IC3

- Temporary operating parameters (for RF, etc.)

When power on the Cordless Handset, the voltage is as follows;
BATTERY(2.2 V ~ 2.6 V: BATT+) 

→ F1 → Q2 (1.8 V), IC1-43pin (2.5V)

The Reset signal generates IC1 (61 pin) and 1.8 V.

When charging the Cordless Handset on the Charger Unit, the charge current is as follows;
DC+(6.5 V) 

→ F1 → R1 → CHARGE+(Charger) → CHARGE+(Cordless Handset) → L4 → Q4 → D7→ F1 → BATTERY+... Bat-

tery... 
BATTERY- 

→ L8 → R45 → GND → L5 → CHARGE-(Cordless Handset)→ CHARGE-(Charger) → GND → DC-(GND)

In this way, the BBIC on Cordless Handset detects the fact that the battery is charged.
The charge current is controlled by switching Q9 of Cordless Handset.

“Battery Low” and “Power Down” are detected by BBIC which check the voltage from battery.
The detected voltage is as follows;

• Battery Low

Battery voltage: V(Batt)   2.25 V ± 50 mV

The BBIC detects this level and "

" starts flashing.

• Power Down

Battery voltage: V(Batt)   2.0 V ± 50 mV
The BBIC detects this level and power down.

The hands-free loudspeaker at SP+ and SP- is used to generate the ring alarm.