In a message dated 5/24/00 2:53:21 PM Eastern Daylight Time, JohnC@ININ.COM
writes:

> I am trying to connect the output of a D/A signal to an open phone line to
>  play audio (sort of similar to the "DTMF decoding with a PIC" thread that
is
>  going on, only I need to transmit DTMF and music).  I have been doing quite
>  a bit of searching for specifications on telco line impedance and so forth,
>  but I have yet to find a definitive guide.  I am also strongly leaning to
>  finding a 3rd party product that would accept a standard 47K ohm impedance
>  signal from an RCA phono plug shielded type of connector.  If anyone has
>  information, especially on the latter, I would really appreciate it.
>
>  Thanks.
>
>
>  John Clark
>  Indianapolis, IN
>
Take a look at the Motorola MC34014P speech circuit for interface to the
phone line.

Hope this helps,

Max