CML Semiconductor Products

Call Progress Tone Detector

FX643

© 1996 Consumer Microcircuits Limited

D/643/4 March 1996

1.0

Features

Provisional Issue

SOIC Packages

1.1

Brief Description

The FX643 decodes the audible tone signals provided by Telecom Systems Worldwide to indicate

Dial, Ringing, Busy, Unobtainable and other stages of a call attempt. Detection of these signals is

essential to applications involving machine dialling or automatic call placement. The FX643 provides

the key features needed for intelligent full-function Call Progress monitoring.

In addition to detecting the full range of standard Call Progress tones, the FX643 adds single and dual

tone decoding for better cross-system Call Progress monitoring. The FX643 also directly identifies the

"US Busy" tones, and the international Special Information Tones, saving the time needed for

"cadence verification" under Busy and Unobtainable conditions. The FX643 will also decode and

indicate speech, or other Non-Call Progress signals: this reduces voice-falsing of Call Progress tones

and adds Voice-Answer as a "connected" prompt.

The FX643 uses new digital signal processing techniques to provide these advantages. It is a low

cost, low power product with superior performance. It is available in industry standard

8-pin and 16-pin packages.