Hi;

 I was wondering if anyone has wrestled with trying to eliminate rs232
line drivers and their associated capacitors from a dongle like device
attached to a PC or similar serial port  I know that I can use a MAX232A
to convert my 16c5X software UART lines to serial levels and vice versa,
however I was wondering since resistors and diodes are cheaper and my
supply voltage is +10v & -10v whether I could condition my input serial
line with a resistor and a zener like so:

                10k
in>------/\/\/\/\/\---------------------------<PIC
                                  |   /
                               ------
                             /   A        3.3v
                                 ---
                                  |
                               ///

and do something as simple with the output like

                                 |/---------/\/\/\/\/\/-------<+10v
PIC>-----/\/\/\----------|
                                 |\
                                 |----------/\/\/\/\/\---------<-10v
                                 |
                                 |-----<TXD (to RXD input of PC Serial
Port)

 I also am hoping for less power consumption with this arrangement but
have just begun to look at the realities here.

 If you have some experience to share in this matter I would greatly
appreciate constructive insight.

Thanks........

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