PRODUCT INFORMATION
FX623
Call Progress Tone Decoder
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
TYP
)
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
volt power supply, the
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
V
SS
CONTROL
CIRCUITRY
TIMER
CHIP SELECT
HOLD
PURS
DIGITAL
FILTER
OUTPUT
LATCHES
LIMITER
XTAL
MEASUREMENT
AND
DECODE
FX623