KX-TDA6381X, KX-TDA6381SX - Panasonic PBX Service Manual (repair manual). Page 12

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This transmits the DTMF signal on the highway timeslot. The different DTMF signals can be transmitted to the optional ports at
the same time.
They are transmitted to the line through CODEC.

During on-hook, transmitting the bell signal to the AC loop in the CR series circuits (C3 and R5) detects the current by Photo
Coupler (PC1,2), and it determines the presence of a bell signal. Software performs the operation for recognition and determina-
tion of a pattern of bell signals.

•  Ring

L1R2PC2(1-2)C3R5L1TH1Tip

In this path, PC1 4-pin converts from High to Low, and a bell signal is detected.

•   Tip

TH1L1R5C3PC2(1-2)R2L1Ring

In this path, PC2 4-pin converts from High to Low, and a bell signal is detected.

VIN[0]

DIAL[0]

VOUT[0]

CPCDET[0]

SHNT[0]

VH1

+15V

DG

+5V

AG

+5V

AG

R

20A

PC5A

1

2

4

R32A

T1A

2

1

3

4

C10A

C11A

C12A

C16A

C8A

C9A

IC1A

1

2

3

4

8

R21A

R22A

R24A

R27A

R

30A

R

34A

R35A

DA1A

1

2

3

C7A

IC1A

5

6

7

R23A

DTMF signal

CODEC

R[0]

T[0]

AG

+5V

DG

DG

DG

DG

DG

+5V

+5V

+5V

+5V

+5V

SFG

R

20A

PC5A

1

2

3

4

R

17A

D2A

R3

A

T1A

2

1

3

4

C1

A

C2

A

C4

A

C8A

D1A

D4

A

R21A

R

11A

R

14A

R15A

R16A

R

18A

R

19A

R1

A

R22A

R2

A

22

R4A

1.2K

R5

A

R6

A

J1A

RL

2

A

4

3

2

1

J4A

PC1A

1

23

4

PC2A

1

2

3

4

PC

4

A

1

2

3

4

L1A

1

2

3

4

C3

A

CN3 2

CN3 3

J7

A

C6

A

C7A

Q5A

E

C

B

ZN

R

2

A

CN2

1

26

D3A

1

2

3

4

TH1A

ZN

R

1

A

RL3A

4

3

2

1

D5

A

SA

1

A

12

3

Q4A

E

C

B

A

Ring

Tip