Call Progress Tone Detector

FX643

© 1996 Consumer Microcircuits Limited

8

D/643/4

1.5.4

Decode Output Truth Table

DETECT3

DETECT2

DETECT1

CONDITIONS

0

0

0

No Signal

1

0

0

Special Information Tone:

Will detect 950, 1400 and 1800Hz tones

0

0

1

Call Progress Low Band:

Will detect 350+440, 400+450 and 440+480Hz tones,

for example

1

0

1

Call Progress Low Band:

Will detect single 400, 425, 440, and 450Hz tones,

for example

0

1

1

Call Progress High Band:

Will detect 480+620Hz tones, for example

1

1

1

Call Progress High Band:

Will detect single 600 and 620Hz tones, for example

0

1

0

Non Call Progress signal, e.g. Voice Activity

1

1

0

Will detect a single tone lying outside the

Call Progress Band and within the Non Call

Progress signal range

Note that: DETECT1 responds to the whole range of call progress signals from 340Hz to 650Hz

DETECT2 responds to higher frequency call progress signals and voice or similar activity

DETECT3 responds to and indicates the presence of a single tone

1.6

Application Notes

1.6.1

General

On power-up, a logic "0" at the ENABLE input may be used to disable and initialise the device.