7

GTR

1

23

4

5

6

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

I

LS

47

µF

1N4148

V

CC

IVLS

MIC1

MIC2

EAR-

EAR+

GREC

470nF

2k

Ω

2.2

µF

300

Ω

15k

Ω

10k

Ω

1.3k

Ω

V

REF

10

µF

47

Ω

47nF

100

µF

V

RING

BUZ

V

MC

V

REF

DTMF

V

RMC

SOFT

AGC

10

µF

100nF

10

µF

560k

Ω

100nF

V

CC

TEA7089A

3.9k

Ω

V

REF

47

µF

620

Ω

13V

1

µF

82k

Ω

33

Ω

C2

4.7nF

1.6k

Ω

100nF

600

Ω

100

µF

I

L

15k

Ω

Sidetone

V

CC

6 bit serial code (00XXXX/Fi/010010) ; OSCIN = 1.79MHz external clock (default mode)

or 3.58MHz external ceramic/crystal (with code ”101000” to select internal oscillator)

Figure 17 : Test 6 (DTMF)

TEA7089A

15/17