The dali can't conmmunicate with the computer

[Freeze]

hello,everyone.
I have done a circuit reference the microchip website information,but i found it can't communicate with the computer. I have checked the rs232 and the Optocoupler ,both of them communicate nomal.And the RB1(signal) input is ok,but the RB4 output is no singal .Does anyone can tell me why .
Really appreciate your help

[mackrackit]

You will need to provide more information.
The chip you are using.
Your code.
How what is connected to what.
And the programming language used.

[Freeze]

hello,Dave.
Thank you for answering me the question.
You can find all the information on this website.
http://www.microchip.com/stellent/idcplg?IdcService=SS_GET_PAGE&nodeId=1824&appnote=en012007
the chip is PIC16F628 which writing in assembly language.
Here is the schematic diagram.6673
Here is the commander software6674
It's always like this: the red light