You are wonderful Ijaz, for helping me that far.

It seems you didn't notice yet that your P3.6 and P3.7 are connected to GND and not to Vcc :))

But if your circuit is working fine as you say then I have to correct the two entries in the AT89S51 table (7) of those two pins in the 'Read Code Data' mode and let them be both 'L' instead of 'H'.

I'll check also my circuit right now. Thank you.

Kerim