HI Veeru - are they sending all values as part of one string?
Before you take substring how do you identify which field the value belongs to?
I mean if you have to 10 fields coming out of ECC, out of which 2 fields doesn't have any values(blanks), how do you apply the substring?
Is there any pattern? like fixed postions or separator between the values?
I hope you consider all these things before you impliment 
Ofcouse,There is nothing wrong in sending all the values as part of one string.