Table 1: Digits vs. input data vs. tone output frequency (serial mode)

Digit

D4

D3

D2

D1

D0

Tone Output Frequency (Hz)

10

0

0

0

1

697

20

0

0

1

0

697

30

0

0

1

1

697

40

0

1

0

0

770

50

0

1

0

1

770

60

0

1

1

0

770

70

0

1

1

1

852

80

1

0

0

0

852

90

1

0

0

1

852

00

1

0

1

0

941

∗

01

0

1

1

941

#

01

1

0

0

941

A0

1

1

0

1

697

B0

1

1

1

0

770

C0

1

1

1

1

852

D0

0

0

0

0

941

—1

0

0

0

0

697

—1

0

0

0

1

770

—1

0

0

1

0

852

—1

0

0

1

1

941

—1

0

1

0

0

1209

—1

0

1

0

1

1336

—1

0

1

1

0

1477

—1

0

1

1

1

1633

DTMF OFF

1

1

1

1

1

—

*Notes: The codes not listed in Table 1 are not used D4 is MSB

Functional Description

The HT9200A/B are DTMF generators for

interfaces. They are controlled by a

serial mode or the parallel mode (for the

HT9200B only).

Serial mode (HT9200A/B)

The HT9200A/B employ a data input, a 5-bit

code, and a synchronous clock to transmit a

DTMF signal. Every digit of a phone number to

be transmitted is selected by a series of inputs

which consist of 5-bit data. Of the 5 bits, the

D0(LSB) is the first received bit. The

HT9200A/B will latch data on the falling edge of

the clock (CLK pin). The relationship between

the digital codes and the tone output frequency

is shown in Table 1. As for the control timing

diagram, refer to Figure 1.

HT9200A/B

5

21st Aug ’98