CML Semiconductor Products
PRODUCT INFORMATION
FX623
Features
Call Progress Tone Decoder
Publication D/623/3 July 1994
Provisional Issue
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
V
DD
SIGNAL IN
DIGITAL
FILTER
LIMITER
MEASUREMENT
AND
DECODE
V
SS
CHIP SELECT
XTAL/CLOCK
XTAL/CLOCK
OSCILLATOR
Clocks
Clocks
DATA
CHANGE
XTAL
HOLD
DATA
OUTPUTS
CONTROL
CIRCUITRY
TIMER
OUTPUT
LATCHES
Q0
Q1
Q2
Q3
FX623
PURS
IRQ
Fig.1 Functional Block Diagram
Brief Description
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.
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
[MIN]
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.
CMLMICRO [ CML MICROCIRCUITS ]
