Hi,
I recently tried serial communications PIC<->PC
and they worked. I used three wires only - TxD, RxD and Ground.
From the PC-side the sofware was under DOS and I
did NOT used BIOS and worked with the port directly.
BIOS INT 14 is not good thing.

From the PIC side the transmitter is simple thing...
just write to TXREG.

For receiving it is good idea to implement timeout checking
and error return to calling routine on the both sides.
The software either does not catch the incoming char
or hangs up forever without timeout check.

It essential that PC's UART and PIC's SCI to operate
at same baud rate. (BRGH bit in TXSTA)

MAX232 is an appropitate IC.

Hope this helps...

Ivan

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> From: TORRENS SR <r139a@SMSERVER2.ULST.AC.UK>
> To: PICLIST@MITVMA.MIT.EDU
> Subject: PIC-PC  INTERFACE
> Date: 15 Mnelbph 1997 c. 13:34
>
> Hi,
> I am building a project using the PIC 16c74.
> Part of it involves interfacing to a PC, I am not to sure how to do
> this. I am thinking of using the Serial Communications Interface
> (SCI), configured as a full duplex asynchronous system, and a
> MAX232 to level shift to RS-232.
> Could someone explain the nature of operation and how I should
> implement it?
>
> Thanks
> Ross..