It was a nice explaination etcshadow!!!! As you have got the X12 file structure properly I can put you an important question... in ISA segment 101th element is called the Acknowledgment Requested.. the details are given in the following link..

www.transman.com/EDI/Specifications/EDI_Implementation_Guide.doc
[download]

I have just gone through the document and stuck in TS997 Here is the explaination of ISA014 ------------------------------------------------

ISA14 Acknowledgement Requested

Code sent by the sender to request an interchange
acknowledgment. Codes used are
0 No Acknowledgment Requested – do not
respond with TS997
1 Interchange Acknowledgment Requested –
respond with TS997 as soon as the
transaction is received
[download]

----------------------------------------------- I have google a lot on TS997 but unable to understand how to send it and use it my perl code.. Can you please help me out for TS997???