Hi All PICers !

Wednesday December 18 1996 15:37,
wsci@NET-MAGIC.NET wrote in PICLIST:

 w> At 6:06 PM 12/18/96, J. Cabral wrote:
 w>
 >> I know that there is a simple circuit (without using MAX232
 >> or 4188/4189) to convert RS232 TTL to RS232 C. The hardware
 >> for communicating from the PC to the PIC is quite
 >> simple! The circuit for communicating from the PIC to the
 >> PC is more complicated (I can't remmember it!) it has a
 >> MOSFET and same zenners. All the hardware needed was once
 >> published in ELEKTOR, but I can't seem to find it! Does
 >> anybody knows the circuit?
 w>
 w> do you have a negative supply?

 It not necessary if you use TxD and RxD.

                            e ----+5v
   RxD_TTL------/\/\/\--- b    p-n-p transistor
                 R1          c ----------------------- RxD_RS232
                             |
                              \
                              / R2
                              \
                              /
                             |_________|\|___________ TxD_RS232
                           ______      |/|   |
                           ______ C1         |
                             |               |
                            _|_              |
                                             |
   TxD_TTL ----------------------------------


R1 - 10k-100k, R2 - 300-4k7, C1 - 10-100uFx16v

   Best Wishes, Alex Torres.
   Kharkov, Ukraine, exUSSR.
   E-Mail To : altor@cook.kharkov.ua   via InterNet
               or 2:461/28             via FidoNet

--- GoldED 2.50.A0531+