RS232 communication between 2 PICs

[Ron]

Hi,

Can anyone help me out please.

I want to communicate between 2 PICs via RS232. I was wondering what is required from a hardware standpoint. Does anyone know where I can see a schematic showing how to do this?

I know to have a PIC talk to a PC I must go through a MAX232 to convert voltage levels. Since I want to talk PIC to PIC are these max232 IC's necessary? Can I simply pass RX/TX through a DB9 on each PCB with only one of the boards RX/TX crossed?

The distance between PICs is about 25 feet.

I have 2 PIC boards built with max 232 on them already (I would prefer to keep them on board). I can cross/uncross the RX/TX or bypass max232 to experiment. I actually have DPDT slide switch on board to allow me to cross/uncross the RX/TX lines.

I realize that this is not a hardware forum, just hoping for a quick and easy answer (are answers ever quick and easy?).

Thank you for your time, it is greatly appreciated.

Ron

[Benj]

Hello

Yes you can either connect the PIC micros up directly or use the max chips to provide voltage boosting and therefore extend the limits of your connection. You will also need a common ground connection between the two devices. If you are connecting the pins directly then it may be worth using 220 ohm resistors between the pins to avoid any accidental damage.