HT9020
Block Diagram
Pin Assignment
Pin Description
Pin Name
I/O
Internal
Connection
Description
When this pin is connected to V
DD
, the chip is in the call
progress tone decoder mode (
CPTD mode
)
When this pin is connected to V
SS
, the chip is in the auto busy
redial controller mode (
ABRC mode
)
DEC/ABRC
I
CMOS IN
OE/HKOFF
I
CMOS IN
CPTD mode:
DIAL, RBK, BUSY and ENV pin tristate output
control pin. OE=V
DD
: Tristate output selected
ABRC mode:
Off hook sense pin
HKOFF=V
DD
: Reset controller and disable ABR operation
2
21st Aug ’98