I don't know if this will help:

http://www.dattalo.com/technical/theory/dtmf.html

If you're doing some sort of telephony project, why not use a voice modem
with TAPI? (No firmware debugging that way) Some VB code for TAPI can be
found here:

http://www.geocities.com/sfrare/vbtapi-c.htm

Good luck,

-Randy Glenn

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-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Shawn Yates
Sent: Wednesday, March 20, 2002 9:11 AM
To: PICLIST@MITVMA.MIT.EDU
Subject: [PICLIST] [EE]: DTMF Decoding


Hello all.

I have a project where I need to get DTMF decoded and into a PC.  I have
looked at it from the route of using VB and a modem to decode it, but this
seems very costly and complex.

Can I decode DTMF easily using a PIC or something then use the PIC to send
data to the PC via USART?  I already have a PIC connected to the PC sending
other things to it, the real question is what do I do to anser a phone when
it rings and then decode DTMF that someone keys in?  Oh, the ability to beep
at the user would be nice also so I can prompt them.

TIA

Shawn

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