Will you please tell me what is 'DFU Data'?

I have a programmable coffee machine, for which I have purchased a
'Connectivity Kit'. The main black box of the kit is connected to the
computer by a Serial Port. A cassette is supplied which can be plugged
into the black box and data uploaded to it. The cassette can then be
removed, carried to where the coffee machine is located, plugged into
the machine, and the data is then downloaded into the coffee machine.
Data from the coffee machine can also be uploaded into the cassette for
reading at the computer. This part is all working correctly.

I now need to download the latest set of software from the 'Connectivity
Server' at the coffee machine factory (in Switzerland) for which I need
to be able to set the "internet connection settings" in order to connect
to it.

The screen for setting the internet connection has two sections. One is
a blank window entitled 'DFU Data'. The other section asks for Proxy
Settings. I have a permanently-on cable connection. Will you please
advise what I have to enter into these two sections.

Many thanks