Hi Kashif,

As someone already pointed out, standard 8051 architecture includes the use the ES bit to enable the serial port interrupts (note the plural) and the EA bit to enable the hardware interrupts globally (You must enable interrupts globally, and then enable or disable the specific ones you want to use). I also understand that you're in a new job and your boss wants everything done yesterday. I strongly, repeat strongly, suggest that you printout and read some of the pages from this web site that are linked to on the left under the "Tutorials" button. There you will find a complete "course" on the 8051, including a special chapter on the serial port interrupts, TI and RI. They even include a short example code. You will also want to printout and read the separate "course" on the 8052. It will take you just a few hours in the evening to thouroughly read through all of it. Then, download the three chapters that they call "the Bible" (also linked to over in the left column). Seriously, from experience I can tell you it's the fastest way to get your feet on the ground and going in this new subject area. By the way, did I say that I "strongly" suggest this.