Functional Description

The HT9020B call progress tone detector can be used in world wide countries. Below is an illustration of a call progress

tone frequency band, and a table of U.S.A. CPT signal is shown for user reference. Usually, HT9020B must work to-

gether with a microcontroller through software to distinguish correct cadence of CPT to fit any country CPT SPEC re-

quirement for world wide application purposes.

U.S.A. Call Progress Tone Signal Format

Tone

Frequency

Condition

Precision Dial Tone

350Hz+440Hz

Continuous high

Old Dial Tone

120Hz (or 133Hz, ..) +600Hz

Continuous high

Precision Busy Tone

480Hz+620Hz

0.5sec high and 0.5sec low

Old Busy Tone

120Hz+600Hz

0.5sec high and 0.5sec low

Precision Reorder Tone

480Hz+620Hz

0.3sec high and 0.2sec low

Old Reorder Tone

120Hz+600Hz

0.2sec high and 0.3sec low or

0.25sec high and 0.25sec low

Precision Ring-back Tone

440Hz+480Hz

2sec high and 4sec low

Old Ring-back Tone

40Hz (or the others) +420Hz

2sec high and 4sec low

Timing Diagram

HT9020B

Rev. 1.20

4

March 31, 2003

2 0 0 H z

3 0 5 H z

6 4 0 H z

8 0 0 H z

. r e q u e n c y

- 5 0 d B m

R e j e c t e d B a n d

C P T I n - b a n d D e t e c t e d

R e j e c t e d B a n d

L e v e l

0 d B m

- 2 7 d B m

Call progress tone frequency band illustration

S I N

E N V

X 1 , X 2

E N