Serial port control problem

[xp95]

Hi everybody,
I am working in project which aim to control 80 device through serial port.
First ,I made a simulation by Proteus and virtual port
Second, I used Micro C for Pic programming
Third, C# 2008 for computer interface

The simulation Succeeded but when i try to apply it on 8 devices in reality its failed ( LEDs open randomize)

Can any on tell me the reason?

Here all project files

ww.4shared.com/file/KDAOA3nY/Final.html

 

[LTX71CM]

How are the eight devices connected? Do you have eight RS232 devices sharing the same port? Are each of the eight devices identical but addressable? More info about your project would help here.

 

[xp95]

I put all project files in this link
4shared.com - online file sharing and storage - download Final.rar
which include some pictures of the circuit and simulation files.

How are the eight devices connected?
I put Rs232 to Rs422 conveter to be able to control over than eight devices then connect it in to PIC16F877A in to register 74HC595 which appear in this picture