The RS-232 signal is quite simple:
    the "0-state"(=nothing is been transmitted) is up-level(12V, I velieve)
    when you wanna thansmit something:
    start bit: send a low-level pulse. This must have 1 bit lenght.
    data bits - I work w/ 8 bits, but I believe it can be modificated
    stop bit - for 1, 1.5 or 2(check the RS configuration in the protocol that
you are using) bit lenght, make the signal up-level.
    if you have something new to transmit, send start bit, ...

    For dual comm(receive and transmit in the same time) using the PIC16F84,
you must to create a RTOS(Real-time op. system), that check the RS input, send
something, and do other things you want.

    The cable: for simplify your programm, do the folowing connections:

(DB9 connector)
1+ 4+6   conected
7+8        conected
2        RX
3        TX
5        GND

    And work, for example, w/ 9600, 8, n, 1

    obs: the lenght of a bit is 1/baud
            eg: w/ 9600, one bit will have 1/9600 seg lenght

"JAM [Naish]" wrote:

> Hi to everybody,
> I have to do a project, and i need all the information i'm able to collect
> about RS232, RS485 and lots of routines in C, ASM, or Pascal, all for PC
> and PIC (16F84).
> Thank you very much for your help.
>
> __________________________________
> e-mail: naish@euskalnet.net
> e-mail: jam_naish@usa.net
> ICQ # 3305163
> visit my homepage: http://fly.to/naisaint

Content-Type: text/x-vcard; charset=us-ascii;
 name="tavaresneto.vcf"
Content-Transfer-Encoding: 7bit
Content-Description: Card for Roberto Fernandes T Neto
Content-Disposition: attachment;
 filename="tavaresneto.vcf"

Attachment converted: wonderland:tavaresneto.vcf 2 (TEXT/CSOm) (0000E781)