HT9020 datasheet(9/12 Pages) HOLTEK

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ABR controller

Initial state:

• RDLO=Hi-Impedance

• RDLI=Hi-Impedance

• BREAK=Low

• ABRI=Low

If a negative transition is received on the ABR

pin, then the Auto-busy-dial function will be

executed, and the LED pin will output a 0.86Hz

(duty=0.25) clock. If the device detects a dial

tone, KEY1 and KEY2 pins output a 100ms

pulse to trigger the redial key of the telephone

dialer. The dial tone will be ignored after the

redial key is triggered.

If a busy/reorder tone for three successive win-

dows is received or the line signal is off for

30.2secs or a dial tone appears again for more

than 7 secs after the number is dialed-out, the

device will turn on the internal register to im-

plement the following control:

• Turn off the filter

• BREAK pin output low for on-hook switch

control

• The on-hook timer starts counting the break

time

After the break timer has timed-out, the redial

will be executed again. If the repeat-number

ends, the OVER pin will output a 100ms high

pulse to automatically reset to the initial state.

If the receiver does not answer within 30 cycles,

a ringback tone is produced, and the OVER pin

will output a 100ms high pulse to automatically

reset to the initial state.

The break time and repeat number setting

SEL1 SEL2

Repeat No.

(times)

Break Time

(seconds)

tB1

tB2

62.8

84.9

32.6

34.9

62.8

64.9

4.65

6.97

HT9020

21st Aug ’98

HT9020 Datasheet(PDF) 9 Page - Holtek Semiconductor Inc

HT9020 Datasheet(HTML) 9 Page - Holtek Semiconductor Inc

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