----------
> De: Jorge M. Cabral <Jorge.Cabral@DEI.UMINHO.PT>
> Para: Multiple recipients of list PICLIST <PICLIST@MITVMA.MIT.EDU>
> Assunto: Re: Help:RS232-TTL <-> RS-232-C
> Data: Quinta-feira, Dezembro 19, 1996 09:35
>
> > do you have a negative supply?
> Yes, pin 20 of RS232 can by toggled to /~-12V.


This is very simple and works just fine

                 +5V
                |
                 e |    10K
                \_b____/\/\/\/\/\_____ to PIC
                 c /
                | PNP
RS-232________|
                \
                /
                \  10K
                /
                |
                |
                -12V

My ASCII art is very bad but I think you can understand.

Octavio
========================================================
Octavio Nogueira
e-mail:   nogueira@mandic.com.br
homepage: http://ourworld.compuserve.com/homepages/tato
voice/fax: +55 11 240-6474
"ProPic" The first Production PIC Programmer running in
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========================================================