Consumer Microcircuits Limited CMX673P1, CMX673E3, CMX673D4 Datasheet

CMX673

Call Progress

Tone Detector

 2001 Consumer Microcircuits Limited

D/673/5 June 2001 Provisional Issue

Features Applications

• Worldwide Tone Compatibility • Worldwide Payphone Systems

• Single and Dual Tones Detected • Telephone Redialling Systems

• Wide Dynamic Signal Range • Dialling Modems

• Fast Response Time • Banking and Billing Systems

• Low Power Operation 500µA at 3.0V • Telecom Test Equipment

• 3.58MHz Xtal/Clock Oscillator • 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 2 D/673/5

CONTENTS

Section Page

1.0 Features and Applications............................................................. 1

1.1 Brief Description.................................................................................2

1.2 Block Diagram ...................................................................................... 3

1.3 Signal List.............................................................................................. 4

1.4 External Components....................................................................... 5

1.5 General Description........................................................................... 6

1.5.1 Overall Function Description..................................................... 6

1.5.1 Software Description.................................................................. 6

1.5.2 Glossary........................................................................................ 6

1.5.3 Block Diagram Description........................................................7

1.5.4 Decode Output Truth Table ....................................................... 7

1.6 Application Notes............................................................................... 8

1.6.1 General.......................................................................................... 8

1.7 Performance Specification.............................................................9

1.7.1 Electrical Performance............................................................... 9

1.7.2 Packaging...................................................................................12

 2001 Consumer Microcircuits Limited 3 D/673/5

1.2 Block Diagram

Figure 1 Block Diagram

 2001 Consumer Microcircuits Limited 4 D/673/5

1.3 Signal List

Package

D4 E3 P1

Signal Description

Pin
No.

Pin
No.

Pin
No.

Name Type

2 3 1 XTAL/CLOCK I/P The input to the on-chip oscillator and external

clock input. Components are on chip.
4 5 2 XTALN O/P The inverted output of the on-chip oscillator.
5 7 3 ENABLE I/P A logic ‘1’ applied to this input enables the

DETECT output. A logic ‘0’ will reset

DETECT output to a logic ‘0’.
7 8 4 DETECT O/P When a call progress signal is detected, this

output goes to a logic ‘1’.

10 13 5 SIGIN I/P Signal input. Signals to this pin should be ac

coupled. The dc bias of this pin is set

internally.

12 15 6 VSS Power The negative supply rail (ground).
14 17 7 VREF O/P Internally generated reference voltage, held at

½VDD.

15 18 8 VDD Power The positive supply rail. This pin should be

decoupled to V

SS

by a capacitor.

1, 3, 6,

8, 9,

11, 13,

16

1, 2, 4,

6, 9,
10, 11,
12, 14,
16, 19,

20

NC Internal Connection. Do not make any

connection to these pins.

Notes: I/P = Input
O/P = Output
BI = Bidirectional