> I am trying to develop an application which will connect to the
> telephone line and when I get an incoming line it shall send a voice
> data on the phone line and then look for key entries from the other
> side ... similar to a voice mail system. I have figured out that I
> would need a DAA to interface to the phone line (of course a one that
> would have a DTMF decoder so that I can get the key entries). Now my
> question is how do I send the voice data out (this voice will be
> pre-recorded on a flash). All the places I have looked say that I
> would need PCM data interfaced to a DSP.
> I do not want to complicate the matter -- I want to make it simple by
> using a PIC Microcontroller.
> So basically this is what I plan it would look like:
> RJ11 DAA Serial Interface PIC Micro Flash
> This should take care of both voice and key entries.
> I have looked into tons of options but cannot figure out a "simple" way > to do this.
The 'simple' way is to buy it 'off the shelf'. It's called "IVR", aka "Interactive Voice Response". Inexpensive (even _free_) software to do this on a PC-type box is readily available. It may require a "voice/data" modem, or a dedicated phone-line interface card.
If you insist on DIY, the answer to "how do i send the voice data out" is 'generate the analog wave-form and impress it on the phone line. If that isn't sufficient 'clue', you don't have the requisite skills to attempt such a project -- use the "simple" way, mentioned in the previous paragraph.
For 'digitalized voice' stored anywhere, you have to have "something" to take that digital data, and convert it back to an _analog_ waveform, to send over the POTS circuit. DSP chips greatly simplify the process.