HT9020 Datasheet, PDF (9/12 Pages) Holtek Semiconductor Inc – Call Progress Tone Decoder & ABR Controller

HT9020
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
0
0
10
62.8 84.9
0
1
10
32.6 34.9
1
0
3
62.8 64.9
1
1
15
4.65 6.97
9
21st Aug ’98