The CMX673 is a low voltage multi-purpose Call Progress Tone detector for use in Public Switched Telephone Network System (PSTN) applications. Call progress detection allows equipment that dials into the PSTN to monitor the progress of the resulting call. Various states such as Ringing, Busy, Not available, and Answer can be determined. Using digital signal processing techniques the CMX673 accurately analyzes tones in the 315Hz to 650Hz frequency band and distinguishes valid call progress tone signals from line noise or voice. This contrasts with other call progress detection devices that are based on simple filtering techniques. When combined with cadence measurement of the CMX673 output, the rapid detect response time of the CMX673 allows it to support a wide range of call progress functions including ‘stutter dial tone’ detection used in voice messaging systems.

FEATUREs
• Worldwide Tone Compatibility
• Fast Response
Stutter Dial Tone
Single and Dual Tones
• Industry Compatible Pin Out
• Wide Dynamic Signal Range
• Low Power: 0.5mA at 3.0V
• 3.0V to 5.0V Operation
• 3.58MHz Xtal/Clock Oscillator

APPLICATIONs
• Worldwide Payphone Systems
• Featurephone active feature confirmation
• Telephone Redialing Systems
• Dialing Modems
• Banking and Billing Systems
• Telecom Test Equipment
• Telecom Security Systems