Yes, availibility is the prime reason in small quantity(as Kamath has suggested) and I want to use it at 57.6 kbps. But I don't know what is SOFT UART(as Erik has suggested)?
I also don't want to use any external UART because I am using 8052 in internal mode and almost all of its ports are used.
Actually Philips had have some derivatives which are out of order now.

Thanks.

Harjit