PRODUCT INFORMATION

Publication D/623/3 July 1994

Provisional Issue

CML Semiconductor Products

Features

Measures Call Progress Tone

Frequencies

[‘Busy’, ‘Dial’, ‘Fax-Tone’ etc.]

Telephone, PABX, Fax and

Dial-Up Modem Applications

Low-Power Requirement

(600µA at 3.3 Volts

for Line-Powered Applications

Custom Tone Decoder

[13 Call-Progress Frequencies

Recognized]

Operates to a 3.579545MHz

Telephone System Clock

Operates Under Simple Logic

or µProcessor System Control

The FX623 is a low-power decoding microcircuit that

measures the frequency of telephone system call

progress tones.

With progress signals input from the telephone line,

this single-chip product is programmed to recognize up

to thirteen of the World's most commonly used

call-progress frequencies, analyze signal quality and

present the measured result as a 4-bit parallel data

word at the tri-state Data Output.

Using the parallel information from the FX623, the

host system suitably configured, can recognize such

call progress information as: ‘Dial’, ‘Busy’, ‘Number

Unobtainable’, ‘Ringing’ and Fax/Modem system

signals.

Brief Description

This information can then be employed in telephone

applications (simple or complex) to control telephone

operations. The data output will require a suitable

software format to analyze the frequency information

from the FX623.

Requiring only a single 3.0

FX623 may be line-powered and will operate under

simple logic or system µProcessor control using the

'Data-Change, 'Hold' and 'Chip-Select' functions.

The FX623, whose small size and low power

consumption makes it ideal for remote applications,

requires a 3.579545MHz telephone system clock or Xtal

input, is available in a 16-pin plastic DIL package.

Fig.1 Functional Block Diagram

XTAL/CLOCK

OSCILLATOR

SIGNAL IN

XTAL/CLOCK

Clocks

Clocks

DATA

CHANGE

DATA

OUTPUTS

Q0

Q1

Q2

Q3

IRQ

V

DD

CONTROL

CIRCUITRY

TIMER

CHIP SELECT

HOLD

PURS

DIGITAL

FILTER

OUTPUT

LATCHES

LIMITER

XTAL

MEASUREMENT

AND

DECODE

FX623