Hi Caisson,
I've added a Max232 to the 16c74 and connected 3 wires(Tx,Rx,Gnd) to a
modem. From the PC side I'm able to dial and connect to the PIC  using
Windows  "Terminal.exe", send a  "Carriage Return" and get the PIC to do
something but not the other way. From the PIC I use CCS C compiler to do
a <printf  "atdt101"> but  there is no dial tone at all.

Best  Regards
Alan Ang


Caisson wrote:

> 1) You will havce to convert the PIC's RS232 signals (Gnd & +5 Volts,
> inverted !)   to true RS232 (+/- 3 to 15 volts).  You could use a
> MAX232
> for this purpose.
>
> 2) A terminal emulation program for a PIC ?  I did not know it had a
> screen
> & keyboard :-)   See your MODEM reference booklet for commands to send
> &
> responses to expect (you can instruct the modem to generate full text
> responses, or numbers only). Try sending a 'ATZ'  to your modem.
> normally
> it will respond with 'OK'.
>
> Greetz,
>   Rudy Wieser