So the third party integrator which processed the transaction as a web service... would then turn around and drop files on an FTP server at a bank, to _actually_ make the ACH happen?
I think maybe OP is essentially a third party integrator?
No... 3rd parties like cybersource act just like banks from the perspective of the network and can initiate transactions. They pay big money to the financial institutions for this level of access... But from a dev perspective they provide a defacto standard for transactions across many institutions and networks
I think maybe OP is essentially a third party integrator?