Hi Hemantth
Software wise RS232 is exactly same like RS422, the only difference is that RS422 uses differential transmission to reduce noise.
Its not clear from your question what you want, if you want to use the uart of the 8052 for RS422, all you have to do is to use the MAX1490 RS422 driver chip. and use the on chip uart of the 8052 as if you are using it for RS232.
If you want to convert pc RS232 into RS422 you have to use MAX232 to translate the RS232 levels into ttl serial and then use MAX1490 to translate from ttl back into RS422 levels and vice versa.
the beauty of the MAX1490 chip is that it has its own DC/DC converter built in and your RS422 is isolated.
Best Regards
Mahmood