# Interactive Voice response systems

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#### phaedrus

##### Member level 4
tcm5589n

Hello ,

I hope this is the right forum in the board to post this query.
I would be designing an interactive voice response (IVR) system using the SIM GSM modem.
The system will pick up the phone at the third ring and give a voice message out :
press 1 for this, press 2 for that , etc etc.
When the person presses the appropriate number some action will be taken by the micro board.
The system also should support making voice calls from this equipment when the above situation is not happening.

I need help on two aspects :
1) How to trap the button pressed by the remote user ?Is there any IC which can do this ?
2) How to have a parallel system for both voice conversation and IVR which can be switched as required ?

Does anyone have a reference design which they can point me to.

TIA
Thomas

#### manish12

##### Advanced Member level 3
voice interactive m.e project +pdf

not exactly , but dialer chip and voice recognition chip is a clue to you .

voice reg chip from SM manufacture

#### phaedrus

##### Member level 4
circuit for cm8870 with gsm modem

Hello ,

I dont need a voice recognition chip for this. Theres a human being listening and pressing the buttons.

#### nandhu015

##### Advanced Member level 5
complete project report on voice response sytstem

most of the interactive voice response system works on dtmf

the tone of the key pressed.

Try using dtmf decoder

Regards
Nandhu

#### phaedrus

##### Member level 4
dtmf voice response

Thanks for that Nandhu.
Yes I am aware of CM8870 to decode the DTMF tones.
The issue is, the GSM modem which I have, has only an UART and a connector for a conventional handset.
Would I be able to pick up the DTMF from the hand set connection and feed it to CM8870 ?

#### manish12

##### Advanced Member level 3
intractive voice respond system

yes , you can use dailer chip means dtmf encode and cm8870 is dtmf decoder .

you can use spk wires to pick it and decode it.

#### phaedrus

##### Member level 4
cm8870 based telephone circuit

Thanks for your reply Manish.
Have you tried this ? Would appreciate if you know any links I can pursue to get some reference schematics.

#### manish12

##### Advanced Member level 3
interactive voice response system circuit

no , but it is proven method to do it ,becoz while we are use telephone switch ,for switching, it is similar one.

in telephone exchange rule , there is concept of local presences , in that local voice signal should (in small amount ) heard in speakers earpieces .

according to this you can execute the same

from the knlg of gsm/tele switch control project.

thank you .

Added after 2 minutes:

#### nandhu015

##### Advanced Member level 5
project circuit for voice response system

I had done project of this kind and works perfectly till now.

Happy and prosperous new year

Nandhu

#### umery2k75

##### Advanced Member level 1
interactive voice response system pdf

Don't use CM8870, instead use CM8880 as this IC is microcontroller/microprocessor compatible.

#### phaedrus

##### Member level 4
gsm module and dtmf decoder concept

Hello ,

Thanks Nandhu and Manish for confirming that the concept is feasible.
Umery I am looking at the datasheet. Thanks for the tip.
I will revert with any queries/results.

#### phaedrus

##### Member level 4
cm8870 gsm

Hi Umery ,

Thanks for your interest. The project which you pointed me to uses land line. Actually I am doing it with a GSM modem at one end.
Hence the main issue was if the DTMF tones would be sent out by the modem over its handset connection.
Going by the posts from our colleagues its seems it is so, I would be making a circuit and testing it out soon.

#### umery2k75

##### Advanced Member level 1
etc sm voice recognition chip

Hi,
You can generate DTMF signal either by IC or by making your own circuit, but I advise you to go for the IC.

You can also use the TCM5589N tone generator IC and simply connect the speaker output with the handset and use the control lines to generate the required DTMF signal to be sent out.It doesn't matter whether you are using the landline or GSM modem, you just needs to have the two analog voice carring wires, just connect it's output in parallel to this one and all is done.GSM modem has nothing to do with it, if you want your GSM SIM modem to pick the phone call on the 3rd ring, program it with
Code:
ATS0 = 3 -> this will force it to pick the call on 3rd ring
AT+CHFA=1 -> set this command for the ear piece configuration

just double check the syntax of commands, to ensure error free operation.

You can use the ISD2560,75,90,120 series ICs for voice generations.

There was an IC with CM8890, if I remember it correctly, but I can't find it's datasheet on internet, so that's why I'm not sure at this time of writing about the IC existence.CM8890 was a both decoder/generator for DTMF.

#### manish12

##### Advanced Member level 3
need datasheet for CM8890 i have it, or for voice chip , i have some number .
do you need it ?

#### umery2k75

##### Advanced Member level 1
Yes, please post for the CM8890, I don't have it's datasheet.

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