Hi Sai,
If you use sender as a business system make technical system as based on that system.
If it is ABAP Based system. I mean you are picking file from application server then go for AS ABAP
if it is webdynpro type system select AS JAVA
if it is other than any third party go for third party system....
Hope this will clear your query.... Please let me know if you require anything from my side.
Cheers,
Cnu