CMX673
Call Progress
Tone Detector
D/673/5 June 2001
Provisional Issue
Features
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Applications
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Worldwide Tone Compatibility
Single and Dual Tones Detected
Wide Dynamic Signal Range
Fast Response Time
Low Power Operation 500µA at 3.0V
3.58MHz Xtal/Clock Oscillator
Worldwide Payphone Systems
Telephone Redialling Systems
Dialling Modems
Banking and Billing Systems
Telecom Test Equipment
Telecom Security Systems
1.1 Brief Description
The CMX673 is a general purpose call progress tone detector for use in Public Switched Telephone
System (PSTN) applications. Call progress detection allows equipment which dials into the PSTN
network to monitor the progress of the resulting call. Ringing, Busy, Not available and Answer states can
be determined. The CMX673 uses advanced digital signal processing techniques to detect tones in the
frequency band 315Hz to 650Hz. The use of DSP techniques allows the CMX673 to distinguish between
valid call progress tone signals and line noise or voice, low false detection rates result. This is in contrast
to other call progress detection devices which are based on simple filtering techniques. The detection
timing of the CMX673 allows it to operate with almost any call progress system. In particular the ‘stuttered
dial tone’ of voice mail messaging systems is supported. The use of digital processing and small
geometry CMOS design techniques allows the CMX673 to offer a complete call progress detector which
analyses both frequency and amplitude in a single 8 pin package. This, coupled with industry leading
performance and substantially lower power supply requirements than comparable devices, demonstrates
CML’s unique capability in this area. A single 3.58MHz crystal ensures accurate and repeatable
performance. With supply requirements between 2.7V and 5.5V the CMX673 can be easily integrated
into a wide range of telecom equipments. The CMX673 is pin to pin compatible with the M980 and TSC
75T980 and SSI980. It is available in DIP, TSSOP and SOIC packages. The CMX673 integrated circuit
coupled with cadence measurement of the signals detected can identify virtually all call progress tones
used worldwide.
©
2001 Consumer Microcircuits Limited
CMLMICRO [ CML MICROCIRCUITS ]
