"traitement" is processing, but I expect you already knew that.

Since it's interface specs, the "collecte" will almost certainly refer to the fact that this processing's job is to 'gather' or collect the data from elsewhere.
It's likely this may involve such things as checking file headers to ensure that the file is not a duplicate or one which has already been processed. It may also involve some basic checking of the format (e.g. that date fields contain dates).
It sounds like this particular process doesn't actually process the data itself, but it checks what it has received, and either accepts or rejects the interface file (but I'm reading between the lines there).

I may think of another term for it later, but for the moment, data collection processing is the best I can think of !