Thanks Andy, and this is my declaration:

1-I'm using Comm port to communicate with the burner board to program the chip throught the PC it's ezy2 programmer

http://chaokhun.kmitl.ac.th/~kswichit.../easy2.htm

I think it's not used as power source due to there's external power source,I'm of course using a voltage converter it's MAX232 chip, and RS232 cable.

2-about the voltage when measure the voltage coming on pin 2 of RS232 cable I found -10.4v I'm using a Multimeter when I've used my serial comm. program written in C++ i detect change in the voltage level due to the characters i've entered on the Keyboard. but when i try to make it with the S/W of the Programmer or Hyperterminal nothing!!

3-I'm very sure of the Program written in C++ because i've tried it alone with 8051 chip with small Assebly program to recieve the character sent by serial port and put it on P2 and It was worknig perfectly ,don't worry I'm taking in consideration : Baud Rate, Stop Bit , Parit and Data bits Number.

By the way I may do somthing wrong when I'm trying to use Hyperterminal so nothing apper on the Port

1-I made a new Connection making Comm1 my connecting port.
2-I've configured data bits,Stop bit and Parity.
3-Then begin to connect when I write somthing to the Keyboard nothing appear on the sending screen.

Thanks Andyw again I hope to here from You soon.
Regardes
Ahmed Barakat