What if those devices don't have hardware flow control implemented? In that case this scheme will fail.

You are right Ijaz, If those 10 devices don't have hardware flow control and if Ravi donesn't have access to changing the stuff to software flow control my scheme will certainly fail.
Ravi has to clarify what exactly are the communication parameters for better understanding and solution of problem.

Don't go on assumptions that he is going to produce million units and his devices allow hardware flow control and he can implement 10 bit banged UARTS and he is going to write a special PC software etc.

You are right Ijaz, assumptions are not good. Ravi only can tell how many devices he is intrested in a handfull or lots.

For small quantites, the best solution is a multi-port RS-232 card.

I accept it. [ If there is no motive of learning new thing and availibility is not an issue. ]
Regards,
Prahlad Purohit