Pin Name

I/O

Internal

Connection

Description

ENV/END

O

CMOS OUT

CPTD mode: While an input signal is within specification,

this pin will output the envelope relative to the input signal

with a typical 40ms timing delay.

ABRC mode: This is an ABR finished indicating signal

output pin. When an ABR counter is full, this pin will output

a 100ms pulse.

DV/LED

O

CMOS OUT

CPTD mode: The call progress tone is decoded in this ready

output pin. This pin can be used to trigger a microcontroller to

read the latched data at DIAL, RBK and BUSY

ABRC mode: ABR indicating signal output. While ABR is

active, this pin will output a 0.86Hz, 25% duty cycle clock.

RTZ/SEL1

I

CMOS IN

CPTD mode: Output data return to zero select pin

cleared when the input signal is out of specification while in

the 2.32 sec time window.

latched until the next valid data is received.

ABRC mode: Numbers of the busy redial and time of break

selection pin.

VREF/SEL2

I/O

CMOS I/O

(VREF:O

SEL2:I)

disabled. All outputs will be pulled low to reduce power

consumption.

ABRC mode: Number of the busy redial and time of break

selection pin.

SIN

I

CMOS IN

AC coupled analog signal input pin

B3/RING

I

CMOS IN

CPTD mode: Received busy tone pattern select pin

are received.

received.

ABRC mode: Ringer detection input pin

VSS

—

—

Negative power supply

2.5~5.5V for CPT mode operation

2.0~5.5V for ABR mode operation

VDD

—

—

Positive power supply, 2.5~5.5V for normal operation

BUSY/

BREAK

O

CMOS OUT

CPTD mode: BUSY=HIGH: The detected input signal is a

busy or reorder tone

ABRC mode: When in ABR mode, the BREAK pin will be

high. After a busy tone is detected it will return low.

When the break timer has timed out, it will return high.

HT9020

3

21st Aug ’98