> 1. DTMF detection
> 2. DTMF generation
> 3. ring detect
> 4. CallerID
>
> trasmission speed is not that important.
>
> 1200 baud is ok.

There is a cool two-chip set designed for very low coat applications
that just came out, the Si2400 + Si3015, two 16 pin SOICs, plus a few
discrete caps gives you a V.22 or V.22 bis modem, dtmf, and caller
id.  It uses a capacitively coupled isolation scheme, so no
transformer!

There is a press release in the August 9 issue of Electronic Design.
I have never heard of them before.  It sounds like the chips are
pointed at the zero cost / high volume market, so it might be
difficult to get small quantities?

Contact information listed as:

Silicon Laboratories
4635 Boston Lane, Austin TX, 78735 USA.
Jim Nohrdem
512-416-8500
www.silabs.com

Hope this helps,

Barry.
------------
Barry King, KA1NLH
Engineering Manager
NRG Systems "Measuring the Wind's Energy"
Hinesburg, Vermont, USA
www.nrgsystems.com