help with connecting MT8870 and ISD chip

isd chip writer

I'm trying to build an audio dial tone. So when the person dials a number on the phone pad, they will be able to hear out loud what number or button they pushed verbally instead of a dial tone.

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Example
User dials 1-800

The user will hear "one" "eight" "zero" "zero"
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The construction of the MT8870 was found online for a beggining
http://www.electronicsforu.com/EFYLinux/circuit/jun2003/CI-2-DTMF.pdf

this was constructed exactly and works just like it says in the pdf file.

Now i have an ISD2590 chip that is capable of recording up to 90 seconds, but i shouldn't need more that 12-15 seconds total. I want to record the numbers verbally and when i dial a number have that specific message play.

I know about trying to address it and in having that message play out but i seem to lack the grasp to capture how.

I looked through the files from:
**broken link removed**

where there is good information in learning how the ISD chips work.


So what i was thinking is that the output of the MT8870 should be plugged to the A4-A7 leaving the other inputs gounded because they will not be needed.

I don't know where to go from there. How to record the messages and play them back when the phone pad is dialed. I thought of using a basic stamp, but only seemed to just add an extra step i dont need.


If anyone can help me out, i would really appreciate it. If i am unclear about anything just say so and ill try to fill you in with what i might not have said.

Thank You

using mt8870 chip with audio dtmf

ok i guess no one huh?

can anyone just help me more with the ISD chip?

mt8870 circuit

Hi,
I think broadly speaking, you need a microcontroller interfaced to the sound IC operating in two modes- Recording mode and Run mode.In the recording mode, the microcontroller selects different memory segment addresses for the chip and using a voice activated switch stores the digit sound in different memory segments. It also means you need the necessary audio circuits on the board. In the run mode microcontroller takes the input from the DTMF receiver and selects the appropriate memory segments to play back the sound.

Regards,
Laktronics

voice messages in to segments playback isd

hi
laktronics is right .U r absolutely need to use a Uc or design your job with array of gates (need to know vhdl) for ISD seri use ISD25120 (25 series is suitable for your use)